This week in weather history we really begin to see the arrival of monsoon season and the heavy rains and flooding it can bring to the Thornton and Denver area.  Be sure to check out the events on the 23rd and what the heavy rain brought to the Thornton area in 2004.

13-5 

In 2008…a streak of 26 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.

18-19

In 2003…heavy rain producing thunderstorms caused flash flooding across southern metro Denver.  Automated rain gages measured 2 to 3 inches of rain in less than an hour.  The heavy rainfall caused many intersections and underpasses to flood…stranding motorists.  Sections of I-25 and I-225 were closed due to the high water.

19   

In 1875…recent heavy rains produced high waters on many creeks and rivers in the area…which threatened the destruction of property at some locations.  Cherry Creek in the city was running the highest in 10 years.  Heavy rain in the mining regions over the last 2 days resulted in water running “everywhere” and the suspension of some work.
 
In 1881…a thunderstorm passing across the city produced lightning with no rain.  A woman was seriously injured when struck by lightning several blocks from the weather office in downtown Denver.
 
In 1934…the temperature reached a high of 100 degrees in downtown Denver.
 
In 1965…hail…rain…and lightning hit west metro Denver. Hail stones as large as 1 1/2 inches in diameter accumulated to a depth of 2 inches in Evergreen where 2.95 inches of rain in 2 hours caused some flooding in the business section of the town.  Lightning caused some power outages.
 
In 1973…two funnel clouds were observed 5 miles southeast of Littleton.  The same funnel clouds were observed for 20 minutes…5 miles west and 5 miles west-southwest of Arapahoe County airport…now Centennial Airport.
 
In 1975…lightning injured a man in Denver and caused power outages in Aurora…Lakewood…Westminster…and west Denver.
 
In 1984…strong thunderstorm winds gusting to 45 mph shattered 7 large plate glass windows at Stapleton International Airport.
 
In 1985…a tornado touched down in the surrey ridge area of northern Douglas County…just west of I-25.  Ten homes were damaged; one under construction was nearly destroyed.  Two vehicles were thrown off I-25 injuring three people.  A pick-up truck was thrown 50 feet by the twister.  In addition…a cluster of severe thunderstorms pounded all of metro Denver with torrential rain…hail…and wind.  The heaviest rain fell in Aurora where one location reported 2.37 inches in just 40 minutes.  One location in northeast Aurora received a total of 4.30 inches from the storm. There was extensive street and basement flooding…and a number of roads were damaged or washed out.  An Aurora boy suffered minor injuries when he was washed into a drainage ditch.  Golf ball size hail in Aurora piled up to 5 inches deep.  An inch of rain fell in 20 minutes at Stapleton International Airport…closing it to air traffic for an hour.  Up to 1 1/2 inches of rain fell in just 15 minutes over central Denver with the high water closing I-25.  The water was so deep on the freeway…that one vehicle was completely submerged and people were diving into the water from the freeway overpass.  Three homes in Littleton were damaged by lightning.  Wind blew out several windows from a high rise apartment building in southeast Denver. Rainfall totaled 1.51 inches at Stapleton International Airport.
 
In 1997…torrential rain and damaging hail pummeled eastern sections of metro Denver.  Hail up to 1.25 inches in diameter fell at the national weather service office on the site of the former Stapleton International Airport.  The hail continued for about 15 minutes and accumulated to a depth of 2 to 3 inches…causing extensive damage to cars in the area.  Heavy rainfall totaled 3.83 inches in about an hour from the nearly stationary thunderstorm.  Numerous cars stalled along I-70…and several homes were flooded in east Denver.  The roof of a building collapsed under the weight of the water.  The next day several “fatalities” were discovered near the national weather service office; two prairie dogs were found dead along with three rabbits that either drowned or were killed by the large hail.
 
In 1999…lightning struck two residences in Littleton…but caused only minor damage.  Lightning triggered a fire at a residence in cherry hills village.  A small portion of the roof and ceiling were damaged before the fire could be extinguished.
 
In 2000…hail as large as 1.25 inches in diameter fell near Roggen northeast of Denver.
 
In 2004…heavy rainfall caused flooding on the Virginia Canyon Road near Idaho Springs…which had to be closed for repairs.
 
In 2006…the temperature climbed to a high of 100 degrees.  The high temperature was not a record maximum for the date.
    
In 2007…a severe thunderstorm produced large hail…up to 1 inch in diameter…about 6 miles north of Northglenn.

Continue reading July 19 to July 25 – This week in Denver weather history →

A typical week during the spring and summer for Denver – tornadoes, hail, damaging winds and more.

19-21

In 1875…smoke from several large forest fires in the mountains was visible from the city on each of these days.
20-21 in 1897…high winds raked the city overnight.  Southeast winds were sustained to 60 mph with gusts as high as 72 mph on the 20th.  Southeast winds were sustained to 57 mph with gusts to 60 mph on the 21st.
 
In 2007…a brief hot spell produced two temperature records. The high temperature of 97 degrees was tied on the 20th. A new record high temperature of 99 degrees was established on the 21st.

21   

In 1927…north winds were sustained to 40 mph with gusts to 44 mph.
 
In 1984…lightning struck and killed two children standing near a tree in a backyard in Lakewood.  Strong thunderstorm downbursts caused a wind gust to 58 mph in Northglenn and knocked down two power poles near Brighton.
 
In 1988…lightning struck a home in Denver…causing about ten thousand dollars damage.  Lightning damaged 3 homes in Littleton…and also hit a house in greenwood village that had been struck by lightning 7 years previously.
 
In 1991…thunderstorms produced widespread hail across metro Denver.  Hail as large as 2 1/2 inches fell at several locations across southwest metro Denver.  One storm spotter reported hail 8 inches deep near the intersection of I-25 and C-470.  Heavy rain with the storms caused some street flooding.  In Commerce City…several cars were under water… And in Westminster a police officer reported water up to the doors of his car.  Damage to homes and automobiles totaled 55 million dollars.
 
In 1992…a tornado touched down briefly near Bennett. Another tornado was briefly on the ground near Strasburg.
 
In 1994…heavy thunderstorm rains caused flooding in metro Denver.  Several vehicles were stalled in the high water on I-25.  Lightning struck an underground natural gas line in Aurora…causing a fire.  Widespread power outages were also observed.
 
In 1996…three homes were struck by lightning in Parker. The lightning struck the garage of the first home…which started a small fire that burned some siding and spread into the attic.  A second home sustained damage to the attic when a small fire was started.  The third home received only minor damage.  Lightning also sparked two small grass fires in the area.  A man in Lakewood received minor injuries when he was struck by lightning while working on a ladder.  A funnel cloud was sighted in Castle Rock.  Strong thunderstorm winds downed a large tree near crossroads mall in Boulder.  A small tornado (f0) briefly touched down near Lafayette.  No damage was reported.
 
In 1997…one inch diameter hail was measured in Boulder.
 
In 2002…a thunderstorm wind gust to 62 mph was recorded at Denver International Airport.
 
In 2005…severe thunderstorms produced hail to 1 inch in diameter in Broomfield along with 3/4 inch hail near Arvada.
 
In 2006…a man riding a motorcycle was struck and killed by lightning on U.S. Highway 36 between church ranch Blvd. And Sheridan Blvd. In Westminster.  After the biker was struck…he and his motorcycle crashed into the center concrete median of the highway.  The lightning bolt left a crater in the highway asphalt that measured 18 inches long…8 inches wide and 4 inches deep.

Continue reading June 21 to June 27 – This week in Denver weather history →

An extremely eventful week in weather history showing just how varied conditions can be.  We of course see typical spring weather like tornadoes and hail but also a touch of snow and this week also marks the anniversary of the start of the Hayman Fire.

2-7  

In 1921…heavy rainfall for nearly a week…on top of streams already swollen by mountain snowmelt…produced widespread flooding over the South Platte River basin…including the tributaries through the canyons to the west and southwest of Denver.  Heavy rainfall over the 6-day period totaled 3.36 inches in Boulder…4.98 inches in Morrison…4.27 inches in Castle Rock…and 2.94 inches in the city of Denver. Rainfall amounts in the foothills were estimated between 3 and 6 inches.  The narrow-gage tracks of the Colorado and southern railroad were destroyed in the Platte Canyon.  From the mouth of the canyon through the city to near Brighton… The river spread from 1/2 to nearly 1 1/2 miles wide… Flooding farm and pasture land and destroying or damaging many bridges.  In the city…many businesses along with as many as 500 homes were inundated…forcing their evacuation. Bridges were swept away.  The high waters flooded the rail yards and stock yards in lower downtown…closing three adjacent packing houses.  The heavy rains also caused flooding on Boulder creek in Boulder on the 6th.
6-7   in 2004…a brief hot spell produced 3 temperature records. High temperatures of 95 degrees on the 6th and 98 degrees on the 7th were record maximum temperatures for the dates. Low temperature of 68 degrees on the 7th was a record high minimum for the date.
 
In 2007…an unusually strong storm system brought very strong winds to the Front Range foothills and urban corridor. Peak gusts included:  92 mph at Boulder…85 mph…2 miles southwest of Boulder…83 mph…10 miles south of Boulder and 55 mph at Denver International Airport.  High winds forced the closure of Mt. Evans Road and Trail Ridge Road.  Several trees were uprooted across the urban corridor.  In Aurora… The driver of a car was injured when some building material blew off the Fitzsimmons complex.  The debris landed on the car and knocked the driver unconcious.  The wind forced the cancellation of 60 flights at Denver International Airport. Xcel reported outages in Boulder…Denver…Lakewood and Longmont.

7    

In 1904…a thunderstorm produced south winds to 40 mph with gusts to 50 mph…but only a trace of rain.
 
In 1942…heavy thunderstorm rainfall in south Denver caused flooding of shops…stalled motorists…and halted tramway service temporarily.  Lightning damaged houses…but there was no loss of life.  Precipitation totaled 0.53 inch in downtown Denver.
 
Continue reading June 7 to June 13 – This week in Denver weather history →

An extremely eventful week in Denver weather history.  Most notably for longtime Thornton and Northglenn residents is the 28 year anniversary of the infamous Thornton Tornado which struck on June 3, 1981.

26-31

In 1995…a cool period with light morning showers and moderate to heavy afternoon showers and thunderstorms pushed rivers already swollen from mountain snow melt over their banks causing minor flooding.  Streams and rivers such as the South Platte and Boulder creek flooded meadowlands…bike paths…roads near streams…and other low lying areas.  No significant property damage was reported and crop damage was unknown.  Rainfall totaled 1.79 inches at the site of the former Stapleton International Airport and only 1.51 inches at Denver International Airport.

29-1 

In 1894…heavy rain combined with snowmelt runoff caused widespread flooding over the South Platte River basin. Rainfall was heaviest in the foothills where 5 to 8 inches were measured over the 4 days.  Heavy rainfall west of Boulder flooded mining towns and damaged mining properties.  In the canyons above Boulder…railroads and roads were washed out along with many bridges.  The floodwaters spread into central Boulder and covered a wide area from university hill north to near Mapleton Hill to a maximum depth of 8 feet.  Many houses were swept away…and every bridge in Boulder was destroyed. A few people…trapped in their homes by the floodwaters… Had to be rescued.  However…the gradual rise of the flood waters resulted in only one death.  Boulder creek spread to a width of nearly one mile in the pasture land to the east of Boulder.  Extensive flooding on left hand creek north of Boulder washed away railroad and wagon bridges.  The heavy cloudbursts caused flooding on bear creek…which washed away bridges…railroad tracks…and structures and destroyed the canyon roadway.  Morrison sustained the heaviest flood damage on bear creek.  In Denver…rainfall totaled only 1.50 inches on the 30th and 31st…but the heavy rainfall on upstream tributaries of the South Platte River caused the river to rise as much as 10 feet above the low water mark in the city…which caused some flooding of pasture land downstream to a depth of 6 feet near Brighton.

30-31

In 1935…heavy thunderstorm rains overnight caused flash flooding east of the city on both Kiowa and Bijou Creeks… Resulting in a total of 9 deaths.  Most of the damage was on Kiowa Creek where there were more structures.  The water rose rapidly during the storm…ripping houses and stores from their foundations and sweeping them downstream. Precipitation in Denver totaled only 0.01 inch.  Hail fell in the city for a short time.  The hail was very small and caused no damage.
 
In 1983…a late storm of rain and snow hit the Front Range. Over an inch of rain fell at some spots…and above 7 thousand feet…1 to 5 inches of snow whitened the ground. Some snow flakes even fell in the western suburbs of metro Denver on the night of the 30th.
 
In 2002…unseasonably warm weather at the end of the month resulted in 3 temperature records.  High temperature of 91 degrees on the 30th equaled the record maximum for the date.  Low temperature of 61 degrees on the 31st was a record high minimum for the date.  High temperature of 93 degrees on the 31st was a record maximum for the date.
31    in 1917…rainfall totaled 0.55 inch and was mixed briefly with snow around midday.  Only a trace of snow fell. Cold temperatures during the day resulted in a high of 44 degrees and a low of 35 degrees.  The month closed as the coldest May on record with a mean temperature of only 48.7 degrees…about 8 degrees below normal.  The cold temperatures during the month had a marked effect on shade trees and shrubs in the city.  Elms were just starting to leaf.  Leaves on cottonwoods and maples were only half formed.  Lilacs were just blooming…and snowball clusters would not bloom for days.
 
In 1959…the public reported a tornado briefly touching the ground 10 miles south of Stapleton Airport.  No damage was reported.
 
In 1984…a thunderstorm microburst produced a wind gust to 67 mph…7 miles east of Boulder.
 
In 1991…hail to golf ball size pummeled southern and southeastern sections of metro Denver and continued on east to Watkins.  Several houses and cars were damaged.  Later… Thunderstorms dumped heavy rain across the city of Denver… Causing street flooding in an area just south of downtown and just northwest of downtown.  Water was up to 10 inches deep over northwest Denver.  A brief tornado touched down in Castle Rock where 3/4 inch diameter hail also fell.
 
In 1993…thunderstorms dropped dime size hail in Commerce City.
 
In 1994…lightning struck an apartment in Louisville and damaged electronic equipment…including a computer.
 
In 2006…a severe thunderstorm produced 1 inch diameter hail near Boulder.

Continue reading May 31 to June 6 – This week in Denver weather history →

This week in Denver weather history shows the extremely wide variety of conditions we can have this year.  From major snow storms to hail dropping thunderstorms, we can see it all.

From the National Weather Service:

24-26

IN 1924…POST-FRONTAL RAIN CHANGED TO SNOW…WHICH BECAME HEAVY AND TOTALED 10.2 INCHES OVER DOWNTOWN DENVER. THE GREATEST AMOUNT OF SNOW ON THE GROUND WAS 6.0 INCHES ON THE 25TH DUE TO MELTING. NORTH WINDS WERE SUSTAINED TO 38 MPH WITH GUSTS TO 42 MPH ON THE 24TH.

25-26

IN 1985…A SPRING STORM BROUGHT MUCH RAIN AND SNOW TO METRO DENVER. THE FOOTHILLS WERE BURIED WITH 15 INCHES OF SNOW AT CONIFER AND 12 INCHES AT EVERGREEN. AT LOWER ELEVATIONS… AN INCH OR MORE OF RAIN FELL IN DENVER AND BOULDER. THE HEAVY PRECIPITATION CAUSED BRIEF POWER OUTAGES IN THE DENVER AREA. PRECIPITATION TOTALED 1.06 INCHES AT STAPLETON INTERNATIONAL AIRPORT…INCLUDING ONLY 0.7 INCH OF SNOWFALL.

25-27

IN 1877…SNOW ENDED AROUND 7:00 AM ON THE MORNING OF THE 27TH… AFTER FALLING CONTINUOUSLY FOR 48 HOURS AND TOTALING AN ESTIMATED 13 INCHES IN THE CITY. THE STORM…LIKELY ACCOMPANIED BY STRONG WINDS…CAUSED TRAINS TO BE DELAYED FOR 2 TO 3 DAYS. ONE OR TWO ROOFS OF SMALL BUILDINGS WERE CRUSHED BY THE WEIGHT OF THE SNOW…AND MANY TREE BRANCHES WERE BROKEN IN THE CITY. THERE WERE A NUMBER OF REPORTS OF LIVESTOCK LOSSES. ONE STOCKMAN LOST 17 HORSES AND SEVERAL CATTLE FROM THE SNOW AND COLD. PRECIPITATION TOTALED 1.30 INCHES FROM THE STORM.

26

IN 1965…WHILE ONLY 0.40 INCH OF RAIN FELL AT STAPLETON INTERNATIONAL AIRPORT…SOME COMMUNITIES IN THE FOOTHILLS WEST OF DENVER REPORTED OVER 30 INCHES OF SNOW FROM THE STORM.

IN 1972…A SPRING SNOW STORM ACCOMPANIED BY THUNDER DUMPED 15.8 INCHES OF HEAVY WET SNOW ON METRO DENVER. STRONG NORTHWEST WINDS GUSTING TO 35 MPH PRODUCED BLOWING SNOW. THE STORM WAS QUITE INTENSE AND GREATLY HAMPERED TRAVEL. HIGH WINDS CAUSED DRIFTS 10 TO 15 FEET DEEP IN SOME AREAS… BLOCKING ROADS AND STRANDING HUNDREDS OF MOTORISTS. AN ESTIMATED 500 TO 600 PEOPLE WERE STRANDED IN THE CASTLE ROCK AREA. RESCUE SERVICE WAS PROVIDED BY HEAVY ARMY EQUIPMENT FROM FORT CARSON. POWER LINES WERE DOWNED…POWER POLES WERE TOPPLED…AND A NUMBER OF STEEL TOWERS CARRYING HIGH VOLTAGE POWER LINES WERE DOWNED. SOME AREAS NORTHEAST OF DENVER WERE WITHOUT POWER FOR A WEEK. A LARGE NUMBER OF CATTLE AND SHEEP WERE KILLED BY THE STORM. THE GREATEST SNOW DEPTH ON THE GROUND AT STAPLETON INTERNATIONAL AIRPORT WAS 12 INCHES. WARM TEMPERATURES FOLLOWING THE STORM QUICKLY MELTED THE SNOW.

IN 1995…THE THIRD MAJOR SNOW STORM OF THE MONTH DUMPED HEAVY SNOW IN AND NEAR THE FRONT RANGE FOOTHILLS. SIX TO 12 INCHES OF HEAVY WET SNOW FELL IN THE WESTERN METRO SUBURBS WITH THE HEAVIEST AMOUNTS ABOVE 6 THOUSAND FEET. BOTH BOULDER AND GOLDEN MEASURED 10 INCHES OF SNOW. ONLY 2.4 INCHES OF SNOWFALL WERE MEASURED AT THE SITE OF THE FORMER STAPLETON INTERNATIONAL AIRPORT. NORTH WINDS GUSTED 28 MPH AT DENVER INTERNATIONAL AIRPORT.

IN 1998…THE LAST IN A SERIES OF APRIL STORMS BLANKETED THE FOOTHILLS WITH HEAVY SNOW. SNOWFALL AMOUNTS INCLUDED: 17 INCHES NEAR BLACKHAWK…15 INCHES AT IDAHO SPRINGS…14 INCHES AT GEORGETOWN…11 INCHES NEAR CONIFER AND MORRISON. ONLY A TRACE OF SNOW FELL AT THE SITE OF THE FORMER STAPLETON INTERNATIONAL AIRPORT. NORTH WINDS GUSTED TO 28 MPH AT DENVER INTERNATIONAL AIRPORT.

Continue reading April 26 to May 2 – This week in Denver weather history →

This week in Denver weather history is one to truly showcase the incredible variety of weather Colorado can receive.  Major snow storms, high winds, warm temperatures in the 80’s and even three reports of tornadoes – one near Thornton 21 years ago – have all been seen this time of year. 

17-19

IN 1920…SNOW FELL ACROSS THE CITY CONTINUOUSLY FOR 57 HOURS… FROM THE EARLY MORNING OF THE 17TH UNTIL 11:40 AM ON THE 19TH.  THE HEAVY WET SNOWFALL TOTALED 18.2 INCHES WITH THE GREATEST ACCUMULATION ON THE GROUND OF 12 INCHES.  WINDS DURING THE STORM WERE STRONG WITH SUSTAINED SPEEDS IN EXCESS OF 27 MPH FOR OVER 40 CONSECUTIVE HOURS…WHICH CREATED NEAR-BLIZZARD CONDITIONS.  THE HIGHEST RECORDED WIND SPEEDS WERE 44 MPH WITH GUSTS TO 50 MPH FROM THE NORTH ON THE 17TH AND 39 MPH WITH GUSTS TO 48 MPH FROM THE NORTHWEST ON THE 18TH.  THE STRONG WINDS PILED THE SNOW INTO HIGH DRIFTS WHICH STOPPED ALL DENVER TRAFFIC. RAILROADS WERE BLOCKED WITH ONLY ONE TRAIN ENTERING THE CITY ON THE 19TH.  ALL INTERURBAN TRAINS WERE BLOCKED…AS WERE THE 13 TROLLEY LINES.  THUS…MANY WORKERS WERE UNABLE TO GET HOME AT NIGHT AND FILLED ALL OF THE DOWNTOWN HOTELS TO CAPACITY.  NO GROCERY OR FUEL DELIVERIES WERE POSSIBLE… EXCEPT MILK AND COAL TO HOSPITALS AND TO FAMILIES WITH BABIES.  NO LIVES WERE LOST IN THE CITY…BUT SEVERAL PEOPLE PERISHED IN SURROUNDING DISTRICTS.  STOCK LOSSES WERE HEAVY ON THE PLAINS.  TEMPERATURES DURING THE STORM WERE IN THE 20’S.

18-19

IN 1884…A MAJOR STORM DUMPED 13.8 INCHES OF SNOWFALL ON DOWNTOWN DENVER.  MOST OF THE SNOW…10.0 INCHES…FELL ON THE 18TH.  LIGHT RAIN ON THE EARLY MORNING OF THE 18TH CHANGED TO HEAVY SNOW AT 8:00 AM AND BECAME LIGHT AFTER 2:00 PM BUT CONTINUED UNTIL 4:00 AM ON THE 19TH.  THE SNOW MELTED NEARLY AS FAST AS IT FELL.  THERE WERE ONLY 3 INCHES ON THE GROUND EARLY ON THE MORNING OF THE 19TH.
 
IN 1941…HEAVY SNOWFALL TOTALED 8.4 INCHES OVER DOWNTOWN DENVER.  NORTHEAST WINDS WERE SUSTAINED TO 17 MPH.
 
IN 1993…SPORADIC HIGH WINDS OCCURRED ACROSS METRO DENVER. SIGNIFICANT WIND GUSTS INCLUDED 97 MPH AT ROLLINSVILLE… 80 MPH IN SOUTHWEST BOULDER…AND 55 MPH AT STAPLETON INTERNATIONAL AIRPORT.  THE STRONG WINDS SNAPPED A PINE TREE TOP…ABOUT 15 FEET LONG AND 8 INCHES IN DIAMETER…WHICH CRASHED THROUGH THE ROOF OF A CHURCH IN EVERGREEN…CAUSING ONE THOUSAND DOLLARS IN DAMAGE.  WIND GUSTS OF 50 TO 60 MPH CAUSED STRUCTURAL DAMAGE TO 3 HOMES UNDER CONSTRUCTION IN BROOMFIELD.  NORTHWEST WINDS GUSTED TO 55 MPH AT STAPLETON INTERNATIONAL AIRPORT.
 
IN 1995…THE SECOND SPRING STORM OF THE MONTH DUMPED HEAVY SNOW IN THE FOOTHILLS.  THE UPSLOPE FLOW ALONG WITH AREAS OF THUNDER SNOW DROPPED 6 TO 12 INCHES OF SNOW IN THE FOOTHILLS WEST OF DENVER AND BOULDER.  SNOWFALL TOTALED 4.6 INCHES AT THE SITE OF THE FORMER STAPLETON INTERNATIONAL AIRPORT…BUT MOST OF THE SNOW MELTED AS IT FELL.  EAST WINDS GUSTED TO 29 MPH AT DENVER INTERNATIONAL AIRPORT ON THE 18TH.

Continue reading April 19 to April 25 – This week in Denver weather history →