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Weather History

September 26 to October 2: This week in Denver weather history

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This Week in Denver Weather History

Denver has been graced with an unusually mild September this year.  That however is not always the case and in fact the weather can be downright winterish as we see in our look back at this week in Denver weather history.

25-26

In 1908…apparent post-frontal rain changed to snow overnight and totaled 6.5 inches in downtown Denver.  This was the first snow of the season.  Precipitation totaled 0.76 inch. North winds were sustained to 39 mph on the 25th.

25-27

In 1996…an early season snowstorm brought heavy snow to the Front Range eastern foothills.  Snowfall totals included:  8 to 12 inches around conifer…7 inches on Floyd Hill…and 6 inches at both Bailey and Chief Hosa. Snowfall totaled only 4.7 inches at the site of the former Stapleton International Airport.  This was the first measurable snow of the season.  After the passage of a strong cold front…north winds gusted to 38 mph at Denver International Airport on the 25th.

26

In 1907…a late afternoon thunderstorm produced hail…0.23 inch of precipitation…and north winds sustained to 24 mph.

In 1927…snowfall of 1.7 inches…mixed at times with sleet… Was the first measurable snowfall of the season.

In 2012…a man was seriously injured when he was struck by lightning outside the Hebrew Educational Alliance as he and his family were getting in their car. The victim stopped breathing but was saved when his wife performed cardiopulmonary resuscitation on him immediately following the lightning strike. He suffered burns to 15 percent of his body which included his legs…chest… abdomen and neck. Lightning also caused 48 outages in Denver which affected 6582 Xcel Energy customers.

26-28

In 1936…the heaviest snowfall ever recorded in September and the heaviest snowfall ever recorded so early in the season dumped a total of 16.5 inches of snow on downtown Denver and 21.3 inches at Denver municipal airport.  The 15.0 inches of snow measured from 6:00 pm on the 27th to 6:00 pm on the 28th is the greatest 24 hour snowfall ever recorded in September.  This was the first snow of the season.  The snow was intermittent through the 26th…but continuous from early afternoon on the 27th to around midnight on the 28th…except for a period of rain during the afternoon of the 28th which contributed to a loss of depth on the ground.  The greatest snow depth on the ground downtown was 13 inches with 8 inches at Denver municipal airport.  There were no high winds with the storm and traffic was interrupted for only a short period.  The storm produced property damage estimated at 7 million dollars.  With trees and shrubs in full foliage…the leaves caught and held the heavy water-laden snow…until the branches snapped from the weight.  More than 3000 workmen were called to remove the debris and snow from the city.  The city firemen who were off duty…as well as all the reserves… Were asked to report to their stations.  All schools in the city remained open…but attendance was only 50 percent of normal.  Grade school students were sent home at noon on the 28th.  The early storm caught stockmen with many cattle still in higher ranges.  Warm weather followed the snow…which had all melted by the end of the month…except for a few inches in sheltered places.

27

In 1877…smoke from heavy forest fires in the mountains spread over the city on upper wind currents.

In 1935…the first snow of the season was 2.8 inches in downtown Denver.  The low temperature dipped to 31 degrees for the first freeze of the season.

27-28

In 1984…heavy snow fell over the plains and foothills. Snowfall amounts ranged from 2 to 5 inches on the plains with up to a foot at higher elevations in the foothills. The main problem caused by the storm was thousands of power outages caused by snow-laden tree limbs snapping and falling onto power lines.  Over 15 thousand homes lost power in metro Denver.  Some cars were damaged by falling trees and limbs.  The snow also caused some flight delays at Stapleton International Airport where 5.1 inches of snow fell and northeast winds gusted to 29 mph.  Maximum snow depth on the ground was 3 inches due to melting.  The high temperature of only 34 degrees on the 28th was a record low maximum for the date and equaled the all-time record for the month at that time.

28

In 1877…heavy dense smoke from mountain forest fires spread over the city.  The smoke was so dense that it obscured the sun at times.

In 1921…post-frontal northeast winds were sustained to 44 mph.

In 1953…a pacific cold front produced a west wind gust to 59 mph at Stapleton Airport where the visibility was briefly reduced to 3/4 miles in blowing dust.  Strong winds were also widespread over Boulder during the afternoon.

In 1960…strong…gusty winds tore the roof from 6 units of a motel on west Colfax Avenue in Denver.  The roofing sailed over the building and crashed down on a truck…wrecking it. The strong winds were the result of an apparent microburst.

In 1999…snow fell in the foothills west of metro Denver and over the plains.  Snowfall totals included 7 inches at conifer.  At the site of the former Stapleton International Airport…3.1 inches of snow were measured.  This was the first snow of the season.  The heavy wet snow snapped branches from fully leafed trees…downing power lines and causing scattered outages.

In 2004…severe thunderstorms produced hail to 3/4 inch in diameter in Littleton and in Douglas County 14 miles northwest of Castle Rock.

In 2012…a weak tornado (EF-0) tornado touched down near Strasburg. No damage was reported.

Continue reading September 26 to October 2: This week in Denver weather history →

Weather History

September 19 to September 25: This week in Denver weather history

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This Week in Denver Weather History

This time of year many folks would consider “snow” a bad four-letter word but living in the Mile High City we can’t rule it out even with it technically still being summer.  In fact, it was only 15 short years ago that we received a significant snowstorm that brought up to 8 inches of snow in the metro area and caused millions of dollars in damage.

From the National Weather Service:

15-19

In 1906…rain on 5 consecutive days totaled 1.61 inches. A thunderstorm occurred on the 17th.  High temperatures ranged from 48 degrees on the 16th to 65 degrees on the 15th.  Low temperatures were in the lower to mid 40’s.

16-19

In 1971…a record breaking early fall snow storm caused extensive damage to trees and utility lines.  The heavy wet snow occurred with little wind…but caused record breaking cold temperatures for so early in the season.  Snowfall totaled 15.6 inches at Stapleton International Airport with most of the snowfall…12.0 inches…occurring on the 17th.  This was the heaviest first snow of the season. The maximum snow depth on the ground was 13 inches. Record low temperatures were set on three consecutive days: 31 degrees on the 17th…23 degrees on the 18th…and 20 degrees on the 19th…which was also a new all-time record minimum for the month at that time.  Record low maximum temperatures were set on 4 consecutive days:  48 degrees on the 16th…35 degrees on the 17th…40 degrees on the 18th… And 42 degrees on the 19th.

18-19

In 1955…heavy rains caused flash flooding across portions of metro Denver.  Rainfall totaled 1.71 inches at Stapleton Airport.

19

In 1955…hail stones to 2 1/2 inches in diameter were reported north of Denver.  The large stones broke many automobile windshields.

In 1963…hail to 3/4 inch in diameter fell in Westminster.

In 1983…an unusually strong cold front roared through metro Denver during the afternoon hours.  At Stapleton International Airport…the temperature dropped 51 degrees… From a sunny 86 degrees to a snowy 35 degrees…in just 7 hours.  Strong winds and a wall of blowing dust followed the front.  Northeast winds gusting to 36 mph briefly reduced the surface visibility to 1 mile in blowing dust at Stapleton International Airport where only a trace of snow fell later.

In 1996…high winds gusting to 84 mph were measured at Golden Gate Canyon in the foothills west of Denver. West winds gusted to only 25 mph at Denver International Airport.

20

In 1921…an apparent Bora produced northwest winds sustained to 44 mph with gusts to 64 mph.

In 1955…hail stones 1/2 to 3/4 inch in diameter were reported across parts of the city of Denver.

In 1992…weather observers at Buckley Air National Guard base sighted two tornados southeast of the base.  The tornados were short-lived and caused no injuries or damage.

20-21 in 1963…heavy rain and hail caused local flooding in southeast Denver.  Thunderstorm rainfall was only 0.60 inch at Stapleton Airport on the 20th.

In 1983…the cold front on the 19th brought an unusually cold air mass into metro Denver for so early in the season.  The temperature dipped to a daily record minimum of 28 degrees on both days.

In 1995…a vigorous late summer storm brought the season’s first heavy snow to portions of metro Denver.  Millions of trees were damaged and power lines downed as 4 to 8 inches of heavy wet snow settled on fully leafed trees in the Boulder and Denver areas.  Branches snapped and trees split under the weight of heavy snow…downing power lines. Firefighters responded to numerous transformer fires. Around 100 thousand people were left without electricity in Boulder and Denver areas alone.  It took over a week to fully restore power to some areas.  Insurance claims were estimated to be around 6 million dollars to homes in metro Denver and about 500 thousand dollars in damage to automobiles.  It was estimated that about 80 percent of 125 million dollars worth of city owned trees in Denver were damaged.  Snowfall totaled 7.4 inches at the site of the former Stapleton International Airport where the greatest depth of snow on the ground was only 4 inches due to melting.  Temperature records were set on the 21st when the thermometer dipped to a record low reading of 27 degrees and climbed to a high of only 36 degrees… Setting a record low maximum for the date.  North winds gusted to 29 mph at Denver International Airport on the 20th.

Continue reading September 19 to September 25: This week in Denver weather history →

Weather History

September 12 to September 18: This week in Denver weather history

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This Week in Denver Weather History

Normally one doesn’t associate tornadoes with September weather in Denver but they can and do happen as we see in our look back in Denver weather history for the week.  We have a couple of occasions of twisters and of a funnel cloud.  Other severe weather like hail, damaging wind and flooding rains have also occurred.   Oh, and should we mention the dreaded “S” word – snow?

5-13

In 2010…the Fourmile Canyon Wildfire…northwest of Boulder… broke out on the morning of the 5th. It originated from an unattended fire pit at a local residence. The wildfire quickly consumed 5 1/2 square miles or 3500 acres the first day…and forced the evacuation of over three thousand residents. Erratic 45-mph gusts sent the fire in two directions at times. Very dry weather conditions preceded the fire. The combination of strong winds…low relative humidities and dry fuels allowed the wildfire spread rapidly through the steep…heavily forested terrain. The flames were reportedly 20 to 50 feet in length. Towns within the burn area included Salina…Wallstreet and Gold Hill. The dry conditions coupled with gusty winds ranging from 45 to 64 mph persisted for several more days. Fire managers used as many as 700 firefighters and support personnel from 35 agencies and seven air tankers to battle the wildfire. A total of 6181 square acres or approximately 10 square miles were burned. The Fourmile Canyon Wildfire was the most destructive fire in Colorado history in terms of the damage to personal property. It destroyed 171 homes with an estimated cost of 217 million dollars.

11-16

In 2013…a deep southerly flow over Colorado… Ahead of a nearly stationary low pressure system over the great basin… Pumped copious amounts of monsoonal moisture into the area. In addition…a weak stationary front stretched along the Front Range foothills and Palmer Divide.  This resulted in a prolonged period of moderate to heavy rain across the Front Range foothills…Palmer Divide…urban corridor. By the 14th…storm totals ranged from 6 to 18 inches… Highest in the foothills of Boulder County. The headwaters then moved down the South Platte River and caused widespread flooding with record flood stages at several locations as it made its way downstream.  The record high flood stages resulted in widespread flooding along the South Platte River basin. The flood damage encompassed 4500 square miles of the Front Range…left 7 dead… Forced thousands to evacuate…and destroyed thousands of homes and farms. Record amounts of rainfall generated flash floods that tore up roads and lines of communication… Leaving many stranded. Nearly 19000 homes were damaged… And over 1500 destroyed. Colorado department of transportation estimated at least 30 state highway bridges were destroyed and an additional 20 seriously damaged. Preliminary assessments of the state`s infrastructure showed damage of $40 million to roads and $112 million to bridges. Repair costs for state and county roads ran into the hundreds of millions of dollars. Miles of freight and passenger rail lines were washed out or submerged… Including a section servicing Amtrak`s iconic California Zephyr. The town of Lyons was isolated by the flooding of St. Vrain creek…and several earth dams along the Front Range burst or were over-topped. Floodwaters swept through Estes Park; damaged hundreds of buildings and destroyed large sections of U.S. 34 from Loveland and U.S. 36 from Lyons to Boulder. U.S. 34 suffered the most damage… With 85 percent of its roadway and bridges destroyed. In Weld County…about nearly two thousand gas wells were damaged and had to be closed off as the floodwaters inundated entire communities. Sewage treatment plants and other utilities were knocked out in a number of towns. Governor Hickenlooper declared a disaster emergency on September 13th…in 11 counties across northeast Colorado including:  Adams…Arapahoe…Broomfield…Boulder…Denver…  Jefferson…Larimer…Logan…Morgan… Washington and Weld. By the 15th…federal emergency declarations covered those counties as well as Clear Creek County. Projected losses from the flooding statewide was nearly two billion dollars in property damage…according to Eqecat… A catastrophe modeling firm.  The damage was most severe in and around Lyons and Boulder.  More than 11 thousand people were evacuated…reportedly the largest since Hurricane Katrina. President Obama declared a state of emergency for Boulder and Larimer counties.  An additional 10 counties were added on the 16th and included: Adams… Arapahoe…Broomfield…Clear Creek…Denver…Jefferson…  Morgan…Logan… Washington and Weld counties. The president also declared a major disaster specifically for Boulder County.  There were six fatalities directly attributed to flash flooding. Two 19-yr old teenagers died on the 11th…after they were swept away by floodwaters after abandoning their car on Lindon Drive in Boulder. In Jamestown…a 72-yr old man was killed when the building he was in collapsed. An 80-yr old Lyons resident died in the early morning hours of the 12th…when his truck was swept into the St. Vrain River near his home. Later on the 12th…a 79-yr old Larimer County resident was killed when she was swept away while trying to climb to safety from her home in Cedar Point. A 61-yr old cedar point resident died when her home was swept down the Big Thompson River by the floodwaters. An 80-yr old Idaho Springs resident drowned in Clear Creek when the embankment he was standing on collapsed. In Boulder…some of the monthly records broken included: one-day all-time record: 9.08 inches which shattered the previous wettest day of 4.8 inches set on July 31… 1919; one-month record of 18.16 inches…which broke the previous all-time monthly record of 9.59 inches set in May of 1995; wettest September on record which broke the previous record of 5.5 inches set in September of 1940; one-year record of 34.15 inches broke the previous wettest year of 29.93 inches set in 1995. At Denver International Airport…the total precipitation for the month of September was 5.61 inches…which was 4.65 inches above the normal of 0.96 inches. This is the most precipitation ever recorded in Denver for the month of September. Daily precipitation records included 1.11 inches on the 12th and 2.01 inches on the 14th.

11-12

In 1974…post-frontal rain changed to snow overnight for the first snow of the season.  Snowfall totaled only 1.8 inches at Stapleton International Airport where north winds gusted to 40 mph on the 11th.  High temperature of only 46 degrees on the 12th set a new record low maximum for the date.

12

In 1887…west winds to 42 mph were recorded in the city.

In 1952…a thunderstorm outflow produced strong southeast winds gusting to 52 mph.  Surface visibility at Stapleton Airport was briefly reduced to 2 miles in blowing dust.

In 1963…a nearly stationary…white tornado near Bennett was sighted from Denver.  No damage was reported.

In 1989…an early snowfall and the first of the season brought 2 to 3 inches of slush to metro Denver.  More snow whitened the foothills west of Denver where 6 inches were measured at Evergreen.  The snow fell on leaf laden trees… And sagging branches onto power lines caused outages.  Much of Denver’s snow fell during the evening rush hour…creating traffic chaos.  Snowfall totaled 2.3 inches at Stapleton International Airport where the maximum snow depth on the ground was only 1 inch due to melting.

In 1994…thunderstorm microburst winds gusted to 67 mph in Boulder.  No damage was reported.

In 2002…a severe thunderstorm produced hail as large as 1 inch in diameter near Castle Rock.

13

In 1899…west winds were sustained to 43 mph with gusts to 46 mph.

In 1928…northwest winds were sustained to 41 mph with gusts to 45 mph.

In 1937…an apparent dry microburst produced brief north winds sustained to 31 mph with gusts to 41 mph.  There was a trace of rain.

In 1982…torrential rains drenched both the foothills and plains from Denver north.  While the heaviest rain occurred north of Denver…just east of Denver 2 1/3 inches of rain fell in 5 hours along with hail that caused minor damage to a few airplanes.  Thunderstorm rainfall totaled 0.83 inch at Stapleton International Airport.

In 1993…an upper level system combined with a cold and moist upslope flow to bring the heaviest snowfall to metro Denver for so early in the season.  Snowfall from the storm totaled 5.4 inches at Stapleton International Airport; however…most of the snow melted as it fell leaving a maximum of one inch on the ground at any one time.  North winds gusted to 21 mph at Stapleton International Airport where a record low temperature of 33 degrees for the date was observed.

In 2002…Friday the 13th proved to be bad luck for several motorists when heavy thunderstorm rainfall caused flooding on I-25 in central Denver.  Water rose several feet under the Logan Street overpass…inundating several vehicles. Some motorists were rescued…while others simply waited atop their cars for the flood water to recede.  The highway had to be closed in both directions for about 3 hours.  The flooding was exacerbated by poor drainage due to the construction along the highway.  A 12-foot drainage pipe had not yet been installed beneath the underpass.  The deluge also flooded several businesses along Broadway.

Continue reading September 12 to September 18: This week in Denver weather history →

Weather History

September 5 to September 11: This week in Denver weather history

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This Week in Denver Weather History

September is typically one of our quietest weather months and in fact it is our sunniest.  That doesn’t however mean we can’t experience weather extremes.  This week in Denver weather history we see everything from scorching heat and severe thunderstorms to snow and damaging wind.  For more about September’s weather, check out our September weather preview.

1-5

In 1995…record breaking heat occurred on the first 5 days of the month when the temperature climbed into the 90’s on each day.  Record high temperatures of 97 degrees on both the 1st and 4th equaled the all-time record maximum for the month.  High temperature of 95 degrees on the 3rd was a record for the date.  High temperatures of 94 degrees on both the 2nd and the 5th were not records.  The low temperature of 64 degrees on the 4th equaled the record high minimum for the date.

1-7

In 1978…the temperature reached 90 degrees or more on seven consecutive days with the highest temperature…94 degrees… Recorded on both the 4th and 6th.

3-6

In 1909…rainfall for the 4 days accumulated to 3.97 inches in Boulder…while in Denver rainfall totaled 2.45 inches on the 4th…5th…and 6th.

5

In 1899…the highest recorded temperature in September…97 degrees…occurred.  The same temperature was also reached on September 4…1960…and September 1 and 4…1995.

In 1940…a severe wind and hail storm confined mostly to the west and north parts of the city occurred shortly after 4:30 pm.  Hail stones ranged in size from 1/4 to 1/2 inch in diameter. In north Denver…hail piled to a depth of 4 inches.  Flooding occurred in one underpass…which stalled 2 cars.  One girl was injured when the weight of the hail flattened a porch on which she stood. Northeast winds were sustained to 29 mph with gusts to 32 mph in downtown Denver.

In 1987…a thunderstorm complex produced hail as large as 1 3/8 inches in diameter…2 miles east of Buckley Field in Aurora.  No damage was reported.

5-9

In 1988…layers of smoke aloft from large forest fires in Yellowstone National Park completely obliterated the sun at times.  At Stapleton International Airport…surface visibility was reduced at times to 5 and 6 miles in smoke.

5-13

In 2010…the Fourmile Canyon Wildfire…northwest of Boulder… broke out on the morning of the 5th. It originated from an unattended fire pit at a local residence. The wildfire quickly consumed 5 1/2 square miles or 3500 acres the first day…and forced the evacuation of over three thousand residents. Erratic 45-mph gusts sent the fire in two directions at times. Very dry weather conditions preceded the fire. The combination of strong winds…low relative humidities and dry fuels allowed the wildfire spread rapidly through the steep…heavily forested terrain. The flames were reportedly 20 to 50 feet in length. Towns within the burn area included Salina…Wallstreet and Gold Hill. The dry conditions coupled with gusty winds ranging from 45 to 64 mph persisted for several more days. Fire managers used as many as 700 firefighters and support personnel from 35 agencies and seven air tankers to battle the wildfire. A total of 6181 square acres or approximately 10 square miles were burned. The Fourmile Canyon Wildfire was the most destructive fire in Colorado history in terms of the damage to personal property. It destroyed 171 homes with an estimated cost of 217 million dollars.

6

In 1940…a thunderstorm pelted the city with small hail. The storm produced some lightning damage.  One woman was stunned by a bolt which struck near her.  Heavy rain from the storm raised the level of Cherry Creek by more than 3 feet during the height of the storm.  Rainfall downtown was only 0.26 inch.

In 1988…strong winds blew down two houses that were under construction in Castle Rock.  Northwest winds gusted to 44 mph at Stapleton International Airport.

In 1993…a man was struck and killed by lightning while standing outside his home in unincorporated Arapahoe County 11 miles south of Denver.  Lightning also struck a cabin in Marshdale…20 miles southwest of Denver…which started a fire and damaged one room and a portion of the roof.

In 1995…hail as large as 3/4 inch in diameter fell in Coal Creek Canyon in northern Jefferson County.

In 2001…a thunderstorm dropped 3/4 inch diameter hail in Aurora near Cherry Creek.

7

In 1875…the creeks were running dangerously high during the night from heavy rains in the mountains.

In 1885…a thunderstorm produced very white hail of irregular shape and about the size of beans.  Precipitation was only 0.10 inch.

In 1971…a vigorous cold front accompanied by a thunderstorm produced wind gusts to 48 mph at Stapleton International Airport and much upslope cloudiness and light rain across metro Denver.

In 1989…widespread thunderstorms produced lightning strikes that knocked out power to about 13 thousand homes in Boulder County. In a rugged area stripped of vegetation by a forest fire earlier in July…heavy rain triggered mud slides that destroyed one home and severely damaged another in Boulder canyon 10 miles west of Boulder. In one home…the mud caved in an exterior wall and poured into the residence only seconds after 2 people had evacuated the premises. Rainfall totaled 1 to 3 inches.  Hail 1 3/4 inches in diameter fell in Nederland…Idaho Springs…and Golden Gate Canyon.  Hail 1 inch in diameter was measured 10 miles north of Golden.

In 1993…thunderstorm winds toppled an overhead sign onto the intersection of I-70 and I-25 in Denver…causing considerable damage to 4 vehicles.  The winds also caused a police car to be blown off the road northeast of Denver. Thunderstorm winds gusting to 66 mph damaged the siding of a residence southeast of Brighton.  A thunderstorm wind gust to 53 mph was recorded at Stapleton International Airport.  Hail to 7/8 inch in diameter fell at Kittredge in the foothills of Jefferson County.

In 1994…lightning severely damaged a public television transmitter atop Squaw Mountain west of Denver.

7-8

In 1884…a windstorm from mid-afternoon until the early morning hours of the 8th produced south winds sustained to 48 mph.  The strong winds toppled several trees in the city.

In 1892…there was a trace of rainfall each day.  This together with a trace of rain on both the 2nd and 3rd was the only rainfall of the month…making the month the driest on record.  The record was equaled in 1944.

Continue reading September 5 to September 11: This week in Denver weather history →

Weather History

August 29 to September 4: This week in Denver weather history

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This Week in Denver Weather History

Certainly this time of year we start to see temperatures drop and the conditions moderate.  This is usually one of Denver’s most pleasant times of years when the heat of summer fades and the snow and cold of winter is still far away.  That however wasn’t the case when the most notable event in Denver weather history this week occurred.  It was in 1961 on the 3rd of September that Denver received its earliest measurable snowfall – 4.2 inches!

19-30

In 1875…grasshoppers appeared in great numbers at 10:00 am on the 19th.  Thousands landed on the ground.  The streets were literally covered with them.  Swarms of grasshoppers were seen on each day.  All gardens in the city were devastated…and in the countryside the grasshoppers were very destructive to ripened grain.  On the 30th the grasshoppers were so numerous as to almost darken the sun.

29

In 1876…after the passage of a gentle rain shower to the east during the late evening hours…the moon shone brightly and a remarkably bright lunar rainbow appeared.

In 1910…an apparent cold front produced sustained northeast winds to 40 mph.

In 1946…the high temperature warmed to only 55 degrees…the record low maximum for the month.

In 1989…a spectacular lightning display knocked out power to 300 blocks in southeast Denver.  One bolt started a fire in a lumber yard in the northeast part of the city…and the attic of a home in the same area was set ablaze by a lightning bolt.

In 1996…3/4 inch diameter hail was measured in Parker.

In 2000…lightning struck two homes in Thornton.  The extent of damage was unknown.

In 2002…two small tornadoes caused damage in southeast metro Denver.  The first tornado…associated with a multi-vortex storm…touched down briefly near E-470 and South Jordan Road.  Some fences were damaged…and a few trees were blown down.  A few of the homes also sustained minor roof damage. Damage from this storm totaled 100 thousand dollars.  The second tornado associated with the storm touched down in a subdivision that was under construction at Gartrell and Arapahoe roads.  Four large condominiums under construction were destroyed.  The most heavily damaged portions of the structures were still in the framing stages.  Adjacent sections where enclosed walls were in place were not destroyed.  A man suffered 4 broken ribs and several cuts and bruises when the trailer he sought shelter in was flipped three times and torn apart by the twister.  Damage from this storm totaled 6 million dollars. A severe thunderstorm produced 1 inch diameter hail near Evergreen.

In 2006…severe thunderstorms produced large hail in the foothills west of Denver.  Hail to 1 inch in diameter fell near Blackhawk.  Hail as large as 7/8 inch was measured near Idaho Springs…along with 3/4 inch hail near Nederland and Conifer.

30

In 1981…60 mph winds were reported in Boulder.

In 2004…a severe thunderstorm produced hail as large as 1 inch in diameter in south Aurora near Cherry Creek.

31

In 1951…hail as large as 1 3/4 inches in diameter caused an estimated 300 thousand dollars damage in metro Denver. Hail as large as 1 1/2 inches in diameter was measured at Stapleton Airport.

In 1978…strong thunderstorm winds tore the roof off an apartment building in Aurora…downed trees…and damaged windows in Denver.  A microburst wind gust to 58 mph was recorded at Stapleton International Airport.

In 1985…a thunderstorm wind gust to 60 mph was clocked at Buckley Field in Aurora.

In 1997…hail to 1 1/4 inches in diameter was measured in Aurora.

In 2006…a female postal worker was struck and injured by lightning while delivering mail in Westminster.

In 2008…lightning struck a home in Brighton…damaging the roof and a bedroom.  The damaged totaled 20 thousand dollars.

1

In 1951…large hail pounded Boulder…causing thousands of dollars in damage to roofs and automobiles.  Heavy thunderstorm rainfall flooded basements and produced widespread street flooding.

In 1966…severe thunderstorms caused local flooding in areas from Denver to the north and east.  There was scattered damage from hail and lightning.  Streets were flooded in Boulder…and streets and basements were flooded in several areas of metro Denver.  The public reported 1 inch diameter hail in Aurora and near Cheery Creek Reservoir. Thunderstorm rainfall totaled only 0.39 inch at Stapleton International Airport.

In 1985…severe thunderstorms dumped heavy rain and hail at many locations along the Front Range from Denver south. The southern and eastern suburbs of metro Denver were especially hard hit.  Rainfall from 1 1/2 to 3 inches caused extensive street flooding in Aurora where two creeks rose out of their banks.  Two homes in the city suffered minor lightning damage.  Almost 4 inches of rain fell in the Parker area.  Hail up to ping-pong ball size piled up to a foot deep and closed a road in Evergreen. Hail as large as 1 3/4 inches in diameter was reported 8 miles northeast of Deckers.  Wind gusts to 65 mph were estimated in southeast Aurora.

In 1990…marble size hail piled up to 2 inches deep in the foothills community of Kittredge…18 miles southwest of Denver.  As much as half an inch of rain fell in just 15 minutes and caused minor road and small stream flooding. A thunderstorm dropped pea to marble size hail and brief heavy rain near Ward road and 64th avenue in Arvada. Minor street and small stream flooding was reported in the area.

In 1995…a strong thunderstorm microburst with only a few drops of rain produced a recorded wind gust to 85 mph at the site of the former Stapleton International Airport. The wind gust occurred at 8:30 pm MDT.  The all-time highest recorded temperature in September…97 degrees…occurred.  The same temperature also occurred on September 5…1899…September 4…1960…and September 4… 1995.
1-5

In 1995…record breaking heat occurred on the first 5 days of the month when the temperature climbed into the 90’s on each day.  Record high temperatures of 97 degrees on both the 1st and 4th equaled the all-time record maximum for the month.  High temperature of 95 degrees on the 3rd was a record for the date.  High temperatures of 94 degrees on both the 2nd and the 5th were not records.  The low temperature of 64 degrees on the 4th equaled the record high minimum for the date.

1-7

In 1978…the temperature reached 90 degrees or more on seven consecutive days with the highest temperature…94 degrees… Recorded on both the 4th and 6th.

2

In 1938…heavy cloudbursts in the foothills near the top of Genesee mountain caused flash flooding on bear creek at Morrison.  Nearly 8 inches of rain fell just north of Morrison in 6 hours and drowned 6 people in a car between Morrison and Kittredge.  Damage was estimated at nearly a half million dollars.  Flash flooding also occurred on South Boulder Creek in Eldorado Springs. Rainfall totaled 4.42 inches in Eldorado Springs…and rainfall was estimated to more than 6 inches in the foothills west of the town.  Many buildings and residences were damaged in Eldorado Springs…and bridges were swept away.  The high waters forced residents from their homes as far downstream as Erie.  This was the flood of record on south Boulder creek.

In 1973…hail to 3/4 inch diameter was reported in Boulder.

In 1987…lightning struck two men who were standing under a tree in downtown Denver.  Both were seriously injured and hospitalized.

In 1996…lightning sparked a brush fire in the south buffer zone of the Rocky Flats Environmental Test Facility.  No structures were damaged…but the fire burned about 100 acres of grassland before being contained.

2-3

In 1892…there was a trace of rainfall each day.  This… Together with a trace of rain on both the 7th and 8th…was the only rainfall of the month…making the month the driest on record.  The monthly record was equaled in 1944.

3

In 1901…a thunderstorm produced rain…hail of unknown size… And south winds sustained to 40 mph with gusts to 43 mph.

In 1961…Labor Day snow storm is the earliest date of the first snow…trace and measurable…of the season.  The heavy wet snow broke many limbs from trees that were still in full foliage.  The storm produced 4.2 inches of snowfall at Stapleton Airport with nearly a foot of snow in western suburbs and in the foothills.  Minimum temperature of 33 degrees was a record for the date and the coldest ever recorded so early in the season.

In 1999…severe thunderstorms dumped large hail across metro Denver.  Hail as large as 1 inch in diameter was measured near Cherry Creek in Aurora and near Bennett.  Hail to 3/4 inch in diameter fell in the city of Denver.

In 2002…a thunderstorm produced a wind gust to 51 mph at Denver International Airport.

In 2003…very heavy thunderstorm rain washed out parts of the Virginia Canyon Road above Idaho Springs.  Up to 4 feet of mud reportedly washed down the road during the storm.  Several vehicles were trapped on the road.  In Idaho Springs…several streets…including the main street… Were also buried in mud and gravel.  Some buildings in town experienced minor flooding…including the basement of the town library and the police station.

3-6

In 1909…rainfall for the 4 days accumulated to 3.97 inches in Boulder…while in Denver rainfall totaled 2.45 inches on the 4th…5th…and 6th.

Continue reading August 29 to September 4: This week in Denver weather history →

Weather History

August 22 to August 28: This week in Denver weather history

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This Week in Denver Weather History

Lightning is a very real danger here in Colorado.  The outdoor-centric lifestyle we lead oftentimes puts us in situations when we are better off heading for cover.  The dangers of not properly taking shelter when lightning is in the area are highlighted by a number of events in our look back at this week in Denver weather history.

19-30

In 1875…grasshoppers appeared in great numbers at 10:00 am on the 19th.  Thousands landed on the ground.  The streets were literally covered with them.  Swarms of grasshoppers were seen on each day.  All gardens in the city were devastated…and in the countryside the grasshoppers were very destructive to ripened grain.  On the 30th the grasshoppers were so numerous as to almost darken the sun.

22

In 1898…an apparent thunderstorm produced southwest sustained winds to 40 mph with gusts to 43 mph.

In 1903…a late afternoon thunderstorm produced rain…hail… And east winds sustained to 40 mph with gusts to 44 mph.

In 1904…the lowest recorded temperature in August…40 degrees…occurred.  The same temperature also occurred on three consecutive days…August 24…25…and 26 in 1910.

In 1965…heavy rain and hail caused some damage from flooding over northern Douglas County from Castle Rock to Franktown.

In 1981…thunderstorms moved across metro Denver.  At least 5 funnel cloud sightings were reported.  Funnel clouds were seen at 96th Ave. And Sheridan Blvd. and at 92nd Ave. and Federal Blvd. In Westminster and 7 miles north of Stapleton International Airport.  Lightning injured two people in Boulder.  A quarter inch of rain fell in just 5 minutes in Brighton.  Up to 3/4 inch of rain doused Parker in 30 minutes.

In 1983…3/4 inch diameter hail was reported at Kittredge… Along with 0.60 inch of rain in 25 minutes.

In 1984…a thunderstorm dumped 4 inches of rain on Brighton in 90 minutes…causing extensive street flooding in the downtown area.

In 1987…over an inch of rain fell in 24 hours throughout most of metro Denver.  A public library suffered water damage to the ceiling…carpet…and a few books.  Rainfall was 0.76 inch at Stapleton International Airport.

In 1990…lightning knocked out power to about 2500 homes in Lakewood for about an hour.

In 1991…National Weather Service personnel at Stapleton International Airport sighted an apparent tornado briefly on the ground 3 miles west-northwest of the airport.  No damage was reported.

In 1995…lightning struck 3 electrical power substations in Louisville.  Residences of more than 4500 people were without power from 30 minutes to more than an hour.

In 1996…between 1 and 3 inches of rain fell across metro Denver.  As a result…several low lying areas were flooded. A bicyclist was swept into a fast moving creek when he tried to cross a flooded bike path.  The man was washed downstream about 15 feet before getting snagged by a tree stump.  He and a man who tried to rescue him received minor injuries.  The heavy rain caused numerous power outages…false fire alarms…and traffic accidents. In Lakewood…telephone service to around 60 thousand residents was knocked out when a switching center was flooded.  Funnel clouds were sighted near Chatfield Reservoir and Highlands Ranch.

In 2000…lightning sparked a blaze which gutted a 10-unit apartment building in Highlands Ranch.  Twenty-eight people were left homeless.  Damage was estimated at 2 million dollars.

In 2007…severe thunderstorms produced large hail…up to 1 1/4 inches in diameter…in the vicinities of Castle Rock… Elizabeth and Franktown.

In 2013…flash flooding occurred in central Douglas County with numerous road closures reported. One of the closures occurred at the Tomah Road exit along I-25…south of Castle Rock. The closure backed up all I-25 the way to Castle Rock. At Denver International Airport…1.94 inches of precipitation was recorded…which set a new record rainfall for the date. The old record was 0.75 inches… set back in 1953.

22-24

In 1987…some locations in metro Denver had a total 3-day rainfall of 2 to 4 inches.  Rainfall totaled 0.96 inch at Stapleton International Airport.

23

In 1900…northwest winds were sustained to 42 mph with gusts to 49 mph.

In 1921…a thunderstorm cloudburst produced 2.20 inches of rainfall in an hour over downtown Denver.  This is the greatest 1 hour rainfall on record at the official observing site in the city.  Precipitation totaled 2.93 inches…which is the greatest calendar day precipitation ever recorded in August.

In 1941…one man was killed by lightning about 2 miles from the official weather station in downtown Denver.

In 1962…a home near Boulder was destroyed by a lightning- caused fire.

In 1968…strong winds buffeted Boulder briefly during the early morning hours.  At the National Center for Atmospheric Research…winds averaged 55 mph with gusts to 85 mph.  Damage was minor.  Northwest winds gusted to 31 mph at Stapleton International Airport.

In 1977…lightning damaged at least 6 homes in Aurora.

In 2008…a landspout touched down near Westcreek in Douglas County.  One man was seriously injured when he tried to escaped several falling trees in his ATV.  One of the trees struck his back and broke two vertebrae.  Another camper narrowly escaped injury.  Seconds after he back up his truck…a tree came down where it had been parked.

Continue reading August 22 to August 28: This week in Denver weather history →

Weather History

August 15 to August 21: This week in Denver weather history

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This Week in Denver Weather History

While not as common this time of year, severe weather can still strike as we close out summer.  Most notable are the heavy rain events that can come along as a result of the monsoon season.  The dangers of these are oftentimes ignored and as we see can oftentimes turn deadly.

15

In 1899…a thunderstorm produced southwest sustained winds to 43 mph with gusts to 46 mph.

In 1972…a pilot reported a funnel cloud briefly touching the ground in open fields…17 miles east-northeast of Stapleton International Airport.

In 1980…thunderstorm winds gusted to 55 mph in Boulder.

In 1982…brief heavy rain and winds estimated as high as 70 mph occurred in the conifer-Evergreen area.  No damage was reported.

In 1990…lightning triggered a small attic fire in a house near Sedalia…20 miles south of Denver.  A furious lightning storm caused widespread power outages across southern sections of metro Denver.  One lightning bolt knocked out an electrical substation…causing a 90-minute blackout in southeast Denver affecting nearly 10 thousand homes and businesses.

In 2007…severe thunderstorms produced large hail…up to 2 inches in diameter…near Larkspur.   Extensive damage to vehicles in the area was reported.  In Parker…lightning struck a residence.  The ensuing fire damaged the attic and top floor; causing $100000 in property damage.

In 2008…at least three homes were hit by lightning during the early morning hours in Arapahoe County.  Lightning also struck two homes in Castle Rock…damaging the roofs.

In 2013…a dry microburst uprooted 30 to 40 large trees across a 12-block area of the Park Hill neighborhood in east central Denver. Several trees were snapped near the base along with numerous branches…8 to 10 inches in diameter. Power poles and lines were also downed with resulted in outages which affected seven hundred residents. One of the downed trees crushed a car`s hood… narrowly missing the driver. At Denver International Airport…a peak wind gust of 22 mph was observed from the southwest.

16

In 1902…a thunderstorm produced west winds sustained to 48 mph with gusts to 60 mph…but only a trace of rain.

In 1952…a thunderstorm wind gust to 50 mph was recorded at Stapleton Airport.

In 1960…lightning struck a warehouse in central Denver… Causing 8 thousand dollars in damage to the building and stored electrical equipment.

In 1975…large hail…1 1/2 to 1 3/4 inches in diameter…fell about 4 miles north of Castle Rock.  Hail caused some minor damage in Aurora.  A funnel cloud was reported 25 miles east of Denver near Bennett.

In 1981…a tornado touched down briefly in open country just to the east of Aurora.  No damage was reported.

In 1982…a thunderstorm wind gust to 61 mph was recorded at Buckley Field in Aurora.  At the same time almost an inch of rain flooded and closed streets in south Aurora.  A woman was hit by lightning just north of Denver.  A house in the area was also struck.

In 1985…a thunderstorm produced strong wind gusts over southern metro Denver.  One strong wind gust hit Cheery Creek Reservoir…capsizing a boat and drowning a man.  The wind gusts…clocked as high as 50 mph…also downed a few trees.

In 1989…1 3/4 inch diameter hail fell at Intercanyon in the foothills of Jefferson County.

In 1990…lightning caused minor damage to a south Aurora home.  No injuries were reported.

In 1994…strong thunderstorm winds caused damage in southern Weld County near Hudson and Fort Lupton.  Two mobile homes were destroyed and a few lost their roofs.  Up to 20 downed power poles and the destruction of two 115 thousand-volt towers caused widespread power outages.  Thunderstorm gust front winds from the north gusted to 48 mph at Stapleton International Airport.

In 2000…lightning ripped most of the roof from a home in southeast Aurora.  The bolt sparked a fire which destroyed the residence.  Damage was estimated at 250 thousand dollars.

In 2002…the temperature climbed to a maximum of 100 degrees setting a new record high for the date.

In 2003…a teenager was injured when he was struck by lightning while camping at Herman Lake…13 miles northwest of Georgetown.  The boy was knocked unconscious and suffered minor injuries.

16-19

In 1979…heavy thunderstorm rains on each of 4 consecutive days dumped a total of 2.62 inches of rain on Stapleton International Airport.  The heaviest rain…1.05 inches… On the 19th was accompanied by 1/4 inch diameter hail.

Continue reading August 15 to August 21: This week in Denver weather history →

Weather History

August 8 to August 14: This week in Denver weather history

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This Week in Denver Weather History

Monsoon season in Colorado typically brings short-lived but heavy rains.  These can result in flash flooding and we see that in our look back at this week in Denver weather history.  Also notable are the number of lightning deaths and injuries as well as hail events and even a swarm of grasshoppers!

8

In 1874…swarms of grasshoppers invaded the city.  Millions of them were seen cruising through the air.  The insects were apparently picked up by a thunderstorm gust front and carried into the city.  The grasshoppers had ravaged crops in surrounding counties for the last month.

In 1878…the highest temperature ever recorded in Denver…105 degrees…occurred at 3:20 pm.  This temperature was equaled on July 20th in 2005.

In 1969…the temperature reached 100 degrees at Stapleton International Airport.

In 1976…in Thornton…a 13 year old boy riding a bicycle was struck and killed by lightning.

In 2000…lightning struck three homes in central Arapahoe County east of Denver.  Damage was estimated at 47 thousand dollars.

In 2003…hail to 1 inch in diameter pelted Denver.  Hail to 7/8 inch was measured in Boulder.

In 2008…heavy rain also caused flash flooding over south Denver and its nearby suburbs. Heavy rain…from 2.5 to 4 inches…fell in less than 90 minutes.  Firefighters rescued 20 people as the water quickly rose along creeks…flooded roadways…and stranded motorists.  Three people had to be rescued along Cherry Creek when the bike path flooded.  In Evergreen…a man suffered minor injuries when he was struck by lightning.  It entered his finger…traveled down his body… And exited his foot.

8-10

In 1979…heavy thunderstorm rains on each of three consecutive days dumped a total of 2.22 inches of rain at Stapleton International Airport.  The heaviest rain… 0.95 inches…fell on the 9th.  Small hail to 1/8 inch diameter fell on the 8th.

8-13

In 1875…clouds of grasshoppers were seen flying through the air on the prevailing winds during each day.

9

In 1900…a thunderstorm produced west winds sustained to 47 mph with gusts to 55 mph…but only 0.01 inch of rain.

In 1902…a thunderstorm produced no rain and north winds sustained to 52 mph with gusts to 60 mph.

In 1934…heavy cloudbursts in the foothills near Kittredge and at the head of Mount Vernon Creek caused flash flooding on both Bear Creek and Mount Vernon Creek at Morrison… Which resulted in 6 deaths and much property damage. The highway in Mount Vernon Canyon was destroyed by the flood waters.

In 1981…3/4 inch hail fell at Kittredge near Evergreen in Jefferson County.

In 1987…3/4 inch hail fell in Boulder and 9 miles northwest of Castle Rock.

In 1995…lightning struck a 16-year-old counselor in the back of the head while he and a friend were standing under a tree at the singing river ranch…7 miles west of Evergreen.  He stopped breathing…but his friend was able to summon help and they were able to revive him.  He was hospitalized for a few days and released.

In 1998…brief…weak tornadoes (f0) were sighted near Bennett and Roggen.  No damage was reported.  Hail as large as 1 inch diameter fell in Franktown with 3/4 inch diameter hail measured near Castle Rock. Thunderstorm winds gusted to 61 mph near Roggen.

9-10

In 2006…mid and high cloudiness overnight on both days resulted in two temperature records.  The low temperature of 71 degrees on the 9th was a record high minimum for the date.  The low temperature of 68 degrees on the 10th equaled the record high minimum for the date first set in 1936.

10

In 1924…0.01 inch of rain fell over downtown Denver.  This along with the 0.01 inch of rainfall on the 4th was the only rainfall of the month…making this the driest August on record in the city.

In 1962…the high temperature reached 100 degrees at Stapleton Airport.

In 1970…hail stones to 1 inch in diameter were reported in the Fort Lupton  area.

In 1972…dry thunderstorm microburst winds gusting to 46 mph briefly reduced the surface visibility to 3/4 mile in blowing dust at Stapleton International Airport.

In 1978…lightning struck two men in Aurora…killing one and injuring the other.

In 1982…a tornado was sighted near Castle Rock and remained on the ground for 10 minutes.  Wind gusts to 60 mph were reported in Castle Rock.  No damage was reported.

In 1994…heavy thunderstorm rains caused flash flooding on Lena Gulch in west metro Denver.  Damage was estimated at 50 thousand dollars.  Lightning struck a house in Westminster…causing a small attic fire.

In 1996…strong thunderstorm winds toppled a tent at a company picnic in Westminster.  Five people received minor injuries when the tent collapsed.  Two cars nearby were also damaged by flying debris.  A weak tornado (f0)…first sighted near Denver International Airport…traveled east to near Bennett and Strasburg.  No significant damage was reported.

In 1998…heavy rain caused flooding and flash flooding problems over southwest metro Denver.  An observer in Lakewood measured 3.26 inches of rainfall in an hour. Several streets were flooded in central Lakewood.  In addition…a trailer park along Lena Gulch in Wheat Ridge was evacuated due to high waters.  One inch diameter hail fell near Roggen.

In 1999…thunderstorm-producing tornadoes…damaging straight line winds…heavy rain…and hail hammered metro Denver.  In the city…small hail and heavy rainfall…up to 2.50 inches an hour…caused a 20-foot by 50-foot section of the roof to collapse at a furniture warehouse.  Damage to the warehouse was estimated at 1 million dollars.  Heavy rain also flooded several underpasses with up to 3 feet of water…which resulted in a number of stalled vehicles.  In Fort Lupton…a tornado bounced across the area.  Spotty damage was reported along a 5-mile path as trees…power poles…and lines were downed.  In addition…an empty semi-trailer was overturned onto another vehicle northeast of the town.  Thunderstorm winds gusted to 81 mph south of Fort Lupton.

In 2004…severe thunderstorms pummeled metro Denver with large hail.  Hail up to 3 inches in diameter was measured 10 miles east of Castle Rock.  Two inch diameter hail fell in Louisville…10 miles north of Hudson…and 1 mile east of Brighton.  Hail to 1.75 inches was reported in Englewood… 1 mile south of Ft. Lupton…and 8 miles east of Boulder. Hail to 1.50 inches was reported around Boulder…near Broomfield…and in Lafayette…Thornton and Greenwood Village. Hail from 3/4 to 1 inch in diameter was found in Broomfield… Brighton…Castle Rock…Denver and Thornton…and near Longmont… Northglenn…Greenwood Village…Morrison…and Wheat Ridge. Severe thunderstorm wind gusts were recorded to 66 mph in Parker and to 60 mph 5 miles northeast of Boulder.  There were no damage estimates from the hail or wind.

11

In 1872…fog was very dense until about 8:00 am.  There was water dripping from the roofs of houses as if it had rained. The rain gage showed 0.01 inch of moisture…even though there had been no rainfall.

In 1927…an apparent dry microburst produced only a trace of rain and brief northwest winds sustained to 34 mph with gusts to 44 mph.

In 1980…hail up to golf ball size caused some roof and car damage in the southern part of Aurora.

In 1990…lightning ignited a storage tank filled with 10 thousand gallons of crude oil in a farmer’s field near Dacono…25 miles north of Denver.  Flames shot to 40 feet high for nearly 2 hours before being extinguished.  A lightning bolt also struck 21 miles north of Denver at an Erie fire station…causing extensive damage to the gas meter and electrical system.  The sudden power surge blew out the station’s television set…a refrigerator…and a pop machine.  Small fires spread throughout the structure… Totally destroying the building’s electrical wiring.  The fires were quickly extinguished by the in-resident fire fighters.  Golf ball size hail was reported in Denver near the intersection of Santa Fe Drive and I-25.

In 1992…dime size hail fell in Westminster.

In 1994…strong thunderstorms produced large hail across northwest and north metro Denver.  One inch diameter hail fell in Brighton with 3/4 inch hail reported in Westminster and at Indian Hills in the foothills west of Denver. Lightning struck a house in Arvada.  The resulting fire destroyed one-third of the house.  Funnel clouds were sighted over Westminster.

In 1997…large hail…strong winds…and torrential rains hammered portions of Lakewood and south Denver.  Nearly 1 inch of rain fell in the span of 10 minutes in south Denver with a storm total of 1.81 inches.  Street flooding was extensive as gutters and other drainage systems in the area were clogged by hail…piled several inches deep…and other debris.  Strong thunderstorm winds to 50 mph and large hail accompanied by heavy rain caused extensive damage to cars…homes…and businesses.  Several trees were downed by the strong winds…and trees were stripped of their leaves by hail.  A water lily exhibition on display at the Denver Botanic Gardens was heavily damaged.  Final estimates of the damage included 60 million dollars to automobiles and an additional 68 million dollars to homes and businesses.  Hail to 1 1/2 inches in diameter fell in south Denver with 3/4 to 1 inch hail in Lakewood.  A man received minor injuries in Aurora when he was struck by lightning while talking on the telephone.

In 2003…hail to 3/4 inch in diameter was measured in Aurora near Cherry Creek.

In 2012…a severe thunderstorm produced a wind gust to 60 mph at Rocky Mountain Metropolitan Airport.

Continue reading August 8 to August 14: This week in Denver weather history →

Weather History

August 1 to August 7: This week in Denver weather history

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This Week in Denver Weather History

August isn’t normally associated with severe weather but our look back at the history books show it certainly can and does happen.  We see many occurrences of dangerous lightning and of particular note is the flood events – a byproduct of the monsoon season the first of August brings.

18-2

In 1987…a streak of 16 consecutive days of 90 degrees ranked 4th on the list of hot streaks.  The record of 24 consecutive days was established in the summer of 2008.

1

In 1888…heavy rain in the mountains and foothills caused flooding on clear creek in Golden.  The high waters also washed away portions of the railroad tracks in the canyon between Idaho Springs and Golden.

In 1901…the temperature reached a high of 100 degrees in the city.

In 1902…the high temperature climbed to 100 degrees in downtown Denver.

In 1914…a thunderstorm produced 1.00 inch of rainfall in just 21 minutes and north winds sustained at 43 mph with gusts to 50 mph.  Rainfall totaled 1.17 inches.

In 1938…the temperature climbed to a high of 100 degrees in downtown Denver…which is the record maximum for the date.  The temperature was also recorded on this date in previous years.

In 1976…flight operations at Stapleton International Airport were suspended for 90 minutes when the airport tower radar was knocked out and water reached a foot deep on some taxi ramps after 1.50 inches of rain fell in one hour.  Heavy rain also caused minor flooding in east Denver and Aurora where lightning damaged the roof of a home and injured the owner.  One young man was swept down a flooded ditch…but was rescued by firemen.  A number of rafts were floated in flooded streets.  Thunderstorm rainfall totaled 1.71 inches at Stapleton International Airport.

In 1978…a tornado damaged a house and broke a power pole 5 miles northwest of Parker.  A microburst wind gust to 52 mph briefly reduced visibility to 1 mile in blowing dust at Stapleton International Airport.

In 1985…heavy thunderstorms roared through the southern and western sections of metro Denver…producing large hail and heavy rain.  Lightning hit a recreational vehicle trailer causing it to burn.  There was a lot of street flooding over western suburbs where rainfall totaled over 2 inches in some areas.  One inch diameter hail was reported in Littleton and near Evergreen.  Hail piled 4 to 6 inches deep at Tinytown in the foothills southwest of Denver.

In 1990…a small rope-like tornado was spotted in open country 15 miles southeast of centennial airport. No damage was reported from the twister.

In 1992…pilots reported a funnel cloud near the construction site of the new Denver International Airport.  A few minutes later…a tornado was reported near Bennett.  The tornado remained on the ground for about 18 minutes and was visible from the national weather service office at Stapleton International Airport.  Thunderstorm wind gusts to 70 mph were reported near Bennett and Watkins with a wind gust to 60 mph at Brighton.  Two men were injured when struck by lightning.  A young man sustained serious injuries when struck by lightning while jet skiing on Cheery Creek Reservoir.  A man received only minor injuries when struck by lightning while golfing in Westminster.

In 1994…heavy thunderstorm rains in the foothills west of Denver caused the closure of the Virginia Canyon Road north of Idaho Springs by rocks and debris.

In 2001…a 34 year old man on the South Platte River bike path in Denver received minor injuries when lightning struck a nearby tree.  Lightning…coupled with strong thunderstorm winds…knocked out electrical power to about 10 thousand homes and businesses in Golden.

In 2006…strong thunderstorms hit southern metro Denver. A severe thunderstorm wind gust estimated to 71 mph knocked down a tree in Aurora near Cherry Creek. Lightning sparked a fire in a home near Lone Tree and struck a transformer at an RTD light rail station at Interstate 25 and Yosemite street.  Heavy thunderstorm rainfall forced the closure of Arapahoe road between Holly and Quebec streets due to high water.  Flooding was also reported near park meadows mall and greenwood village.  Heavy rainfall also caused flooding in Highlands Ranch…Lone Tree…and Parker.  Water up to 6 inches deep was reportedly running over the roads.

2

In 1878…the high temperature reached 100 degrees in downtown Denver.

In 1911…an apparent dry microburst produced sustained west winds to 42 mph.

In 1972…one workman was killed and another injured when a strong gust of wind destroyed a partially completed apartment building in south Denver.  Hail to 1 3/4 inch diameter fell in Golden.

In 1973…hail to 3/4 inch diameter was reported in Boulder.

In 1986…a major outbreak of severe thunderstorms occurred along the Front Range.  Thunderstorms developed explosively.  Some places were hit by large hail twice. Two inch diameter hail broke car windows on I-25 west of Brighton…and up to 1 1/4 inch hail broke windows in Thornton.  Baseball size hail damaged several planes near Watkins.  Funnel clouds were sighted around Aurora.  Hail over 1/2 inch in diameter covered the ground 3 to 4 inches deep at Hudson northeast of Denver.  Most of the hail fell north of metro Denver…but 3/4 inch diameter hail was measured at Stapleton International Airport.  Total damage from the hail storms this day was estimated at over 10 million dollars.

In 1991…late afternoon thunderstorms produced heavy rain across metro Denver.  Two feet of water covered parts of I-25 in southeast Denver…while one foot of water covered parts of U.S. Highway 285 in Englewood.  Thunderstorm rainfall totaled 0.50 inch at Stapleton International Airport.

In 2001…severe thunderstorms producing heavy rain and hail… Either washed out or damaged several County roads in the Watkins and Bennett areas.  A small tornado (f0) touched down near Bennett…but did no damage.  Hail as large as 1 3/4 inches in diameter fell near Watkins.  One inch diameter hail was measured near Hudson and Keenesburg.

In 2008…strong winds blew several trees down in Denver… Damaging homes and downing power lines.  A peak wind gust of 67 mph occurred at Centennial airport…with gusts to 60 mph estimated in Denver.  A peak wind gust of 37 mph was measured at Denver International Airport.  An elderly man was killed when a wind damaged tree broke free and crushed him while he attempted to remove it.  The downed power lines caused outages to about 500 Xcel energy customers.

Continue reading August 1 to August 7: This week in Denver weather history →

Weather History

July 25 to July 31: This week in Denver weather history

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This Week in Denver Weather History

Colorado’s unofficial severe weather season is during the months of May and June.  However, as we look back in Denver weather history, we see that July can oftentimes hold its own.  Many occurrences of flooding, scorching heat, and even tornadoes have been recorded.  Most notably, this week marks the 24th anniversary of the Big Thompson Flood – Colorado’s deadliest weather disaster ever.

7-25

In 1934…a streak of 15 consecutive days of 90 degrees ranked 5th on the list of hot streaks.  The record of 24 consecutive days was established in the summer of 2008.

13-5

In 2008…a streak of 24 consecutive days of 90 degrees shattered the previous record of 18 consecutive days established in 1901 and 1874.   Ironically…no new single day record high temperatures were set in the month of July. In August however…a record of 104 degrees was set on the 1st…and another record of 103 degrees was set on the 2nd. In addition…a record low min of 70 degrees was set on August 2nd.

18-2

In 1987…a streak of 16 consecutive days of 90 degrees ranked 4th on the list of hot streaks.  The record of 24 consecutive days was established in the summer of 2008.

20-25

In 1965…heavy showers and thunderstorms doused metro Denver with significant rain each day.  Rainfall for the six days totaled 5.16 inches at Stapleton International Airport. Massive rainfall occurred on the 20th…21st…and 25th… Flooding streets and basements and causing streams to overflow.  The heaviest rainfall…2.05 inches…at Stapleton International Airport occurred on the 25th.

24-25

In 2003…maximum temperature of 100 degrees on the 24th was a record high for the date.  Low temperature of 73 degrees on the 25th was a record high minimum for the date.

25

In 1875…brief heavy rain and hail lasted only 5 minutes… But the 1/4 inch diameter hail covered the ground to a depth of 1/2 inch and made the streets look like there had been snowfall.  There was much crop damage…especially to corn…and some sheep were killed.  Precipitation totaled 0.51 inch in the city.

In 1896…a heavy thunderstorm produced sustained northwest winds to 45 mph with gusts to 50 mph and 1.02 inches of rain.

In 1965…a cloudburst dumped 1.99 inches of rain in 30 minutes at Stapleton International Airport.  The storm was accompanied by strong winds gusting to 70 mph.  The heavy rain flooded numerous streets in east Denver and Aurora. One inch diameter hail accompanied a cloudburst…9 miles southwest of Denver.  A funnel cloud was sighted 25 miles northwest of Denver.  In Aurora…there were unofficial reports of 2.30 inches of rain in 40 minutes and 3.30 inches of rain in 30 to 40 minutes.  Rainfall totaled 2.05 inches at Stapleton International Airport.  Rainfall of 2.42 inches for 24 hours on the 24th and 25th was the second greatest on record for July.

In 1977…a tornado touched down briefly in Aurora southeast of Cheery Creek Reservoir.  No damage was reported. A funnel cloud was sighted for 4 minutes by national weather service personnel 10 miles north of Stapleton International Airport near Henderson.

In 1991…heavy rain…up to half an inch in 10 minutes…caused flooding in Westminster…Northglenn…and north Denver where a section of railroad track was washed away.  At Stapleton International Airport…heavy thunderstorm rain totaled 1.85 inches and briefly reduced the visibility to 1/4 mile. Hail to 1/8 inch in diameter was also measured.  A tornado touched down briefly near Fort Lupton.  No damage was reported.

In 1998…heavy monsoonal thunderstorm rains caused flooding and flash flooding in eastern and southern sections of metro Denver…including Englewood and Aurora…when about 2 to 3 inches of rain inundated the area.  Both I-25 and I-70 were closed for 2 to 3 hours as several low lying areas became impassable due to the high waters.  The water was estimated to be 15 feet deep in one flooded underpass along I-25.  As a result…the freeway was closed from south of 6th avenue to university blvd.  Standing water forced the closure of I-70 at gun club road east of Denver.  In Englewood…U.S. Highway 285 was closed…when high water made it impassable.  Several cars were reportedly floating down the roadway near Sheridan Blvd.  In Aurora…the intersection at Yale Ave. And chambers rd. Was flooded by high water up to 4 feet deep when a spillway on the high line canal was breached.  Lightning also knocked out 11 transformers across metro Denver…causing several small fires and scattered power outages.  Flood and flash flooding also occurred north of Strasburg when as much as 2.51 inches of rain fell in an hour.  The deluge resulted in considerable flooding of local streets and County roads.  Torrential rainfall of 2 to 3 inches in less than an hour triggered a flash flood in Virginia Canyon.  County Road 279 between Idaho Springs and Central City was closed for two days to clear debris from mudslides.  Several cars in Idaho Springs were washed off the road…and numerous basements were flooded in town.  Thunderstorm rainfall totaled 2.69 inches at Denver International Airport.

In 2001…lightning struck two homes in Lafayette…damaging the roof and attic of one and shorting out the electrical system in another.  Hail to 1 3/4 inch in diameter was measured 7 miles north of Castle Rock with 3/4 inch hail 7 miles north of Sedalia.

In 2005…heavy thunderstorm rain in the vicinity of the overland wildfire burn scar triggered a mudslide in Jamestown.  Rocks the size of bowling balls…along with silt and mud slid down the mountain into the town.  No one was injured.  One parked car was buried by the debris.

In 2006…heavy thunderstorm rainfall caused flash flooding 1 mile north of the town of Westcreek in southwestern Douglas County.  Several maintenance roads were washed out by the floodwaters.

Continue reading July 25 to July 31: This week in Denver weather history →