Our weekly look back at Denver weather history always has interesting items but this week one stands out in particular. Denver has never officially recorded snow during the month of July. However, before official records began in 1882, the U.S. Army Signal Service weather observer reported snow on July 17, 1872!

From the National Weather Service:

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.

15-16

In 2006…a brief mid July hot spell resulted in two 100 plus degree high temperatures and two daily maximum temperature records. The high temperature climbed to 101 degrees on the 15th and 103 degrees on the 16th at Denver International Airport.

16

In 1911…thunderstorm winds were sustained to 44 mph from the northwest.

In 1959…a thunderstorm produced 3/8 inch diameter hail and a wind gust to 60 mph at Stapleton Airport.

In 1972…two tornadoes were sighted by the public to the southeast of Aurora. No damage was reported.

In 1978…a thunderstorm wind gust to 52 mph was recorded at Stapleton International Airport.

In 1980…a severe thunderstorm ripped through metro Denver… Producing torrential rain…large hail…and strong winds. In Aurora…winds gusted to 65 mph with hail up to 1 1/2 inches in diameter and half an inch of rain in just 10 minutes. Stapleton International Airport was closed for an hour. Large hail also fell in southeast Denver…Lakewood…Parker… And Castle Rock. Up to 1 1/2 inches of rain fell in just 40 minutes. Heavy rains in wheat ridge flooded a shopping center…breaking windows and doors…while causing 100 thousand dollars in damage. Some roofs and windows were damaged throughout metro Denver. At Stapleton International Airport where west winds gusted to 49 mph…1/4 inch hail and 0.77 inch of rain fell.

In 1983…severe thunderstorms dumped large hail over much of metro Denver. Hail to 3/4 inch in diameter fell in Littleton and Northglenn…with 3/4 to 1 inch hail in Arvada…1 to 1 1/2 inch hail in extreme northwest Denver…1 3/4 inch hail in Lakewood…1 1/2 inch hail in south Arvada and just northeast of Aurora…and 1 5/8 inch hail on Green Mountain.

In 1994…spotters reported a brief tornado touchdown in an open field just north of Fort Lupton. No damage or injuries were reported.

In 2000…very moist and unstable weather conditions…along with low level upslope flow during the late afternoon and evening…combined to produce heavy thunderstorm rainfall… Which caused urban and small stream flooding across metro Denver. Rainfall amounts generally ranged from 1 to 3 inches with the heaviest rainfall occurring during the evening hours. Two miles east of white ranch in northern Jefferson County… An automated rain gage measured 3.86 inches of rain. Since the rain fell in a relatively open area…no flood damage was reported. However…in greenwood village near the intersection of Peoria and Belleview…the streets were closed for several hours with as much as 2 feet of standing water covering the roadways. Two campers near Mt. Evans were injured by lightning and stranded overnight by the inclement weather. Both received minor injuries.

In 2003…the high temperature of 101 degrees was a record maximum temperature for the date.

In 2004…locally heavy rainfall of unknown amount caused parts of the Virginia Canyon Road near Idaho Springs to wash out. The road had to be closed temporarily.

In 2005…the temperature climbed to a high of 102 degrees at Denver International Airport. This was a new record maximum temperature for the date at the time.

16-18

In 1997…an extended hot spell resulted in 3 temperature records being set. The maximum temperature reached 98 degrees on each of the days…setting records on the 16th and 18th. The low temperature of 71 degrees on the 17th was a record high minimum for the date. The high temperature reached 100 degrees on the 17th at the site of the former Stapleton International Airport.

17

In 1872…the U.S. Army Signal Service weather observer recorded snowfall during the early morning hours in the hand written daily weather journal: “rain commenced at 1:30 a.m. changing about 3 a.m. to snow & in about half an hour to rain again; it continued until 6 a.m.” this is the only recorded occurrence of snowfall in Denver in July…but this report is not included in the “official” station snowfall records…which did not begin in Denver until January 1…1882. The low temperature on this morning was 45 degrees…which is sufficiently cold for the occurrence of light stratiform snowfall.

In 1918…a thunderstorm produced hail to an inch in depth on the ground. The stones varied in size from a small cherry stone to nearly 1/2 inch in diameter. Not much permanent damage was done to crops. Precipitation totaled 0.40 inch…and northeast winds were sustained to 25 mph with gusts to 28 mph.

In 1971…the temperature reached a high of 101 degrees at Stapleton International Airport.

In 1983…3/4 inch diameter hail fell at Lafayette…while golf ball size hail pelted Brighton and Northglenn where funnel clouds were also sighted.

In 1986…1 1/2 inches of rain fell in an hour and 15 minutes in southeastern Aurora. Thunderstorm rainfall totaled 0.89 inches at Stapleton International Airport.

In 1987…a small tornado was sighted near Watkins…in the vicinity of Front Range airport.

In 1997…lightning ignited an oil well tank holding 10 thousand gallons of oil…16 miles northwest of Bennett. About 200 acres of grassland burned before the fire could be extinguished. A dry microburst produced a wind gust to 52 mph at Denver International Airport.

In 2000…an estimated 2 inches of rain fell in less than an hour…causing two secondary roads in buck and miller gulches in the hi meadows fire burn area to wash out. Water also covered Jefferson County road 68 which connects to Bailey. Homeowners in pine valley estates attempted to divert some of the runoff by piling stacks of hay on the hillside above their homes. Torrential rainfall…up to 3.50 inches an hour…caused flash flooding along Whiskey Gulch near Elizabeth. Several roads were washed out and basements flooded during the storm. Along County Road 13… About 6 miles north-northwest of Elizabeth…rushing water washed away a 15-foot section of the road. The floodwaters forced debris and mud into four huge culverts…sending water over the road. At Denver International Airport…an United Airlines ground crew worker was struck by lightning as she was loading a Boeing 747 jumbo jet. The woman was injured when lightning either hit the jet or the loading equipment that she was working near. The 25-year-old woman received only minor injuries.

In 2006…outflow from severe thunderstorms to the southeast of metro Denver produced southeast sustained winds to 35 mph with gusts as high as 52 mph at Denver International Airport during the late evening.

In 2011…a deluge of heavy rain occurred in and around Nederland when the storm dumped nearly 2 inches of rain in 30 minutes. The heavy rainfall washed out hillsides and dirt roads. In Nederland…a culvert became blocked with debris and forced the water to spread into a nearby bookstore. The rainfall also damaged several residential roads in the Sunnyside Subdivision and Navajo Road became impassable. Several homes suffered flood damage as the runoff from a nearby Beaver Creek jumped its banks and flooded garages…living rooms and bedrooms of nearby houses.

18

In 1874…the temperature climbed to 90 degrees or more for the 18th consecutive day…setting a record. The record was equaled from July 6th through the 23rd in 1901.

In 1902…a thunderstorm produced northwest winds sustained to 45 mph with gusts to 48 mph along with rain and hail. Total precipitation was 0.53 inch.

In 1911…a shower produced north winds sustained to 44 mph.

In 1958…1 1/2 inch diameter hail fell 9 miles west-southwest of Stapleton Airport.

In 1981…a thunderstorm bombed Evergreen with about 2 inches of rain in 45 minutes. A heavy hailstorm left 5 to 7 inches of hail on the ground in some places and stopped the Colorado Open golf tournament at Hiwan.

In 1985…over 2 inches of rain doused the southwest suburbs of Denver. Street flooding occurred in the Montbello area of northeast Denver.

In 1992…nickel size hail fell across central Douglas County near Castle Rock and Sedalia. One inch diameter hail fell in Castle Rock.

In 1993…thunderstorm winds gusted to 60 mph at Strasburg east of Denver.

In 2004…heavy thunderstorm rainfall caused flooding over parts of the Virginia Canyon Road near Idaho Springs. Several sections of the roadway were washed out. The road was closed temporarily for repairs.

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.
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.

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.

19-23

In 2005…the high temperature climbed above 100 degrees on each of the 5 days with readings of 101 on the 19th…105 on the 20th…104 on the 21st…and 102 on both the 22nd and 23rd. A new record maximum temperature for the month of July of 105 degrees was set on the 20th…which also equaled the all time record maximum for Denver of 105 degrees first set on August 8th in 1878. Daily maximum temperature records were set on each day…and the 5 day period equaled the record for the most consecutive days of 100 degrees or more first set from July 4th through 8th in 1989. The intense heat resulted in a high use of electricity for cooling purposes. The demand for electric power exceeded the supply and rolling black-outs… Each lasting about an hour…were scheduled across metro Denver during the afternoons and early evenings.

20 Continue reading July 16 to July 22: This week in Denver weather history →

Our look back at this week in Denver weather history demonstrates why July is considered the Mile High City’s stormiest month. Many instances of flooding rains, damaging wind and hail and dangerous lightning are seen in our past.

From the National Weather Service:

1-18

In 1874…a streak of 18 consecutive days of 90 degrees tied for second with another streak that was later set in the summer of 1901. The record of 24 consecutive days was established in the summer of 2008.

1-31

In 2012…it was the hottest July on record in Denver since weather records began in 1872. The average temperature for the month was 78.9 degrees which was 4.7 degrees above normal. There were 27 days in which the high temperature equaled or exceeded 90 degrees…which established a new record. There were also 7 days in which the temperature equaled or exceeded 100 degrees which tied the record set in 2005.

6-23

In 1901…a streak of 18 consecutive days of 90 degrees tied for second with another streak set in the summer of 1874. The record of 24 consecutive days was established in the summer of 2008.

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.

9

In 1872…a very brisk wind between 2:00 pm and 3:00 pm spread a cloud of dust and sand into the city.

In 1874…northeast winds at sustained speeds up to 36 mph blew immense clouds of dust from the prairie through the streets of the city around mid-morning. The houses across the street from the weather station were not visible at the peak of the storm.

In 1875…heavy thunderstorm rains caused stream flooding… Which damaged nearly all railroads into the city. Rainfall in the city was only 0.14 inch.

In 1953…heavy thunderstorm rains caused an estimated 2 million dollars damage from flooded stores and basements across metro Denver. The flood waters reached a depth of 3 feet on streets in some sections of the city…damaging streets and automobiles. The heavy rainfall at Lowry Air Force Base totaled 3.90 inches. At Stapleton Airport where the heavy rain briefly reduced the surface visibility to 1/2 mile…only 1.05 inches of rain were measured. North winds gusting to 52 mph caused some damage in east Denver.

In 1982…two small tornadoes were spotted east of Rocky Flats… And a tornado touched down briefly 5 miles east of Brighton. No damage was reported.

In 1984…heavy rain fell over southern sections of metro Denver. Rainfall totaled 1.50 inches in just 15 minutes between Littleton and Sedalia.

In 1987…a thunderstorm microburst produced a wind gust of 58 mph at Erie north of Denver.

In 1988…hail to 3/4 inch in diameter piled up 2 to 4 inches deep in Idaho Springs. Some basements were flooded and several thousand gallons of fuel were contaminated when water flooded a gasoline storage tank. A tornado sighted near Manilla 5 miles west of Bennett remained on the ground for 9 minutes. No damage was reported.

In 1990…a severe thunderstorm produced a tornado and heavy rain over northeast metro Denver. As much as 4 inches of rain fell in just 20 minutes in Commerce City…causing the South Platte River to rise quickly and flood lowland areas. The raging flood waters caused extensive damage to a 30-foot stretch of railroad track embankment…destroyed a railroad trestle and a nearby garage…and washed away a vintage 1960’s show car near East 58th Avenue and York Street. The car was found a couple of miles downstream in a pool of deep mud and murky water. Rainfall totaled 1.34 inches at Stapleton International Airport where 1/2 inch diameter hail fell. The same thunderstorm produced a brief tornado in a vacant field near 64th Avenue and Tower Road just east of the Rocky Mountain Arsenal. No damage was reported from the twister. Lightning from the storm caused power outages to as many as 7 thousand homes and businesses.

In 1996…a tornado (F0) was reported 5 miles south of Hudson. No damage was reported. Twin weak tornadoes (F0) formed for a short time near the northeast runways at Denver International Airport. Less than 15 minutes later…a weak tornado (F0) touched down in the employee parking lot at DIA. Several car windows were blown out…and a few vehicles sustained minor body damage from flying debris. Several signs were also blown down. Later…twin weak tornadoes (F0) touched down again in open country between DIA and Watkins.

In 2004…severe thunderstorms produced hail to 3/4 inch in diameter near tiny town and wind gusts to 66 mph in Bennett. A thunderstorm wind gust to 56 mph was measured at Denver International Airport.

In 2005…a thunderstorm produced a wind gust to 54 mph at Denver International Airport.

9-10

In 1980…a series of severe thunderstorms hit metro Denver… Dumping heavy rain and producing a spectacular lightning display lasting for several hours. A number of homes were damaged by lightning. Winds gusted to 60 mph at Stapleton International Airport where about half an inch of rain fell in just 10 minutes along with 1/4 inch diameter hail. The evening thunderstorms continued into the early morning hours with total rainfall of 1.35 inches at Stapleton International Airport.

In 1998…thunderstorm rainfall totaled 2.04 inches at the site of the former Stapleton International Airport.

10

In 1878…a lunar rainbow was observed during a light mist and fog.

In 1895…the temperature warmed to a high of only 53 degrees… The all-time record lowest maximum temperature for the month of July.

In 1967…golf ball size hail damaged aircraft at Jefferson County Airport near Broomfield.

In 1983…two people were injured when struck by lightning just southwest of Morrison. A man was injured when he was swept downstream by a flash flood on a tributary of clear creek in the canyon 8 miles west of Golden. Heavy thunderstorm rains caused mudslides which closed several roads. Rainfall amounts included: 1.75 inches in 20 minutes in southeast Denver…1.26 inches in 35 minutes in Boulder…2.14 inches in 2 hours in Lakewood…1.70 inches in 45 minutes in Aurora…and 1.25 inches in 30 minutes atop Floyd Hill in the foothills west of Denver.

In 1992…storm spotters reported 3/4 inch diameter hail near the construction site of the new Denver airport just northeast of the city.

In 1995…microburst winds toppled a pine tree 60 feet high and 2 feet in diameter in Denver. The tree fell and injured a man nearby. Microburst winds to 59 mph broke the glass on a door at the national weather service forecast office at the site of the former Stapleton International Airport.

In 1998…thunderstorm rainfall totaled 2.35 inches at Denver International Airport.

In 2000…three children were injured…one critically…when lightning hit a nearby tree at panorama point atop Flagstaff Mountain just west of Boulder. Lightning hit the tree…entered the ground…then struck the children. Lightning sparked a grassfire that burned about 50 acres at the Rocky Flats Environmental Test Facility. Also… Lightning sparked at least 6 fires in the Hudson and Keenesburg areas as thunderstorms…accompanied with heavy rain…large hail…and tornadoes…moved through southern Weld County. Over 2 inches of very heavy rain caused flooding along an I-76 exit ramp near Keenesburg. The fire department rescued 15 stranded motorists as high water inundated sections of the exit ramp and adjacent highway. Basements were also flooded in Keenesburg. One home reportedly had 7 feet of standing water in the basement before the rain subsided. A weak tornado (F0) touched down briefly near Brighton…but caused no damage.

In 2001…a severe thunderstorm dumped 7/8 inch diameter hail in wheat ridge.

In 2002…severe thunderstorms pelted the southern suburbs of metro Denver with large hail. Hail as large as 3 inches in diameter fell 6 miles southeast of Parker. Other large hail reports included 2 inch diameter hail around centennial airport and 3/4 inch hail near Sedalia and Deckers. Hail as large as 3/4 inch was also reported in Broomfield. Runoff from heavy thunderstorm rainfall in the Hayman fire burn area flooded lost creek ranch with up to 18 inches of water just off State Highway 126. Floodwaters damaged a very expensive rug in the lodge. A driveway to a residence was washed away. In Douglas County…runoff damaged forest access roads in the Turkey Creek drainage.

In 2011…a severe thunderstorm produced intense microburst winds in southeast Boulder County. A peak wind gust to 75 mph was recorded in Superior with gust to 58 mph…2 miles south of Lafayette. At Denver International Airport…a peak wind gust of 31 mph was recorded.

11

In 1872…heavy rainfall started at 4:00 pm and continued into the night. The heavy rainfall damaged homes and buildings in all parts of the city. Rainfall totaled 1.64 inches.

In 1888…the temperature reached 100 degrees in downtown Denver.

In 1954…the high temperature climbed to 102 degrees at Stapleton Airport.

In 1970…a girl walking in a park in southeast Denver received eye and facial injuries when lightning struck nearby. Lightning also caused numerous power outages and heavy rainfall produced local flooding at several locations across metro Denver.

In 1974…large hail up to 1 1/2 inches in diameter fell in Thornton.

In 1990…the worst hailstorm in American history in terms of dollar damage at the time battered metro Denver. Storm damage totaled 605 million dollars…as it cut a 5-to 10-mile wide swath from just southeast of Estes Park to northeast of Colorado Springs. Hail as large as baseballs (2.75 inches) pounded metro Denver. Hardest hit areas were southeast Boulder County…the Jefferson County Airport in Broomfield… Arvada…east Wheat Ridge…southwest and south-central Westminster…west Thornton…northwest…west-central and downtown Denver…northeast and east-central Lakewood…just east of Littleton…portions of Arapahoe County west of I-25… And northern and central Douglas County near Castle Rock and Franktown. Golf ball to baseball size hail severely damaged roofs on thousands of homes and buildings…battered tens of thousands of automobiles…windows…signs…street lights…and traffic signals…stripped paint…awnings…and trim from buildings…punched holes in the roofs of two homes in Arvada…knocked out power and telephone service to thousands of homes and businesses…defoliated thousands of trees…ripped up greens and fairways on a number of golf courses…and severely damaged several aircraft tied down at Jefferson County Airport. Hail the size of baseballs fell for several minutes in old town Arvada. Later…golf ball size hail and heavy rain pummeled two northwest Denver amusement parks. Hardest hit was Elitch Gardens Amusement Park where 47 people were injured and received treatment for bumps…cuts…and bruises at local hospitals. Many of the injured were stranded on rides during the storm when power failed. Hail clogged storm sewers…causing rain water to back up 3 to 6 feet deep on some roads and intersections in Arvada. Several basements were flooded. In some places hail was washed into drifts several feet deep. In addition… The storm spawned 2 small tornadoes. One touched down briefly in Lakewood near 6th avenue and Kipling Blvd….but did no damage. In Castle Rock…a tornado (F1) did heavy damage to some homes and vehicles in the Founders Village development near Ridge Road.

In 2001…lightning struck two homes in Thornton. Most of the damage was confined to the attics of both homes. Hail as large as 3/4 inch in diameter fell in Keenesburg…Longmont… And near Boulder.

In 2011…severe thunderstorms developed over parts of Adams and Denver Counties. At Denver International Airport…a severe thunderstorm produced a peak wind gust to 66 mph…with another gust to 59 mph measured in Denver. In Commerce City…the intense winds blew down a large tree.

Continue reading July 9 to July 15: This week in Denver weather history →

As we near the end of July the weather in Denver tends to be a bit more stable. That doesn’t mean the severe weather threat disappears as can be seen at our look back at this week in Denver weather history. Particularly notable are lightning injuries and deaths, flash flood events and even tornadoes.

From the National Weather Service:

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

In 1896…heavy cloudbursts in the foothills west of Denver caused flash flooding on Bear Creek…Clear Creek…Golden Gate Gulch…and Mount Vernon Creek…resulting in a total of 27 deaths. The downpour dislodged large Boulders…one of which crushed a house. The heavy rain also caused a dam on cub creek to wash out…adding even more water to the flood. A wall of water as high as 10 feet flooded Evergreen and passed down bear creek…washing away many structures along the way. The flood crest produced 3 feet of water in downtown Morrison during the early evening. Flash flooding on Mount Vernon Creek added to the flooding in Morrison. In Golden…the flooding washed out bridges on clear creek and on Cresman and Tucker gulches and forced the closure of the power plant. In Denver…a thunderstorm produced hail of unknown size during the afternoon and rainfall of 1.23 inches overnight.

In 1958…a thunderstorm wind gust to 52 mph was recorded at Stapleton Airport.

In 1965…heavy rain caused flooding on clear creek and tucker gulch in Golden and west Denver. Damage in Golden was estimated at 80 thousand dollars. Heavy rain south of Denver washed out temporary earthen bridges constructed following the June floods in Castle Rock…Littleton… Englewood…and Denver. Bear creek in south Denver reached flood stage. A cloudburst on cub creek in Evergreen washed out bridges and roads. Heavy rain fell over all the Denver and Aurora areas…causing some flooding of roads…streets… And bridges. A man drowned in a flooded irrigation canal near Hudson. Heavy rain caused flooding of streets and roads in Blackhawk and central city. Hail caused minor damage in Idaho Springs.

In 1967…seven bridges were washed out along a normally dry creek bed south of State Highway 7 west of Brighton. One car was washed into the creek when a bridge gave way.

In 1970…hail stones to 1 1/4 inches in diameter fell in the foothills of Jefferson County southwest of Denver.

In 1971…golf ball size hail was reported in foothill areas of Jefferson County west of Denver. A funnel cloud was sighted in Aurora. Wind gusts estimated at 60 mph…hail… And heavy rain up to an inch in 15 minutes caused local flooding and some other damage in several areas of metro Denver. Hailstones to 3/4 inch in diameter fell 7 miles southeast of Denver.

In 1973…a thunderstorm wind gust to 52 mph was recorded at Stapleton International Airport where one inch diameter hail was measured.

In 1981…strong winds downed a power line in northeast Denver. Wind gusts to 50 mph were recorded at Chatfield Reservoir.

In 1987…3/4 inch diameter hail fell 5 miles northeast of Commerce City.

In 1996…hail…up to 1 3/4 inches in diameter…fell at Chatfield Reservoir. Hail to 3/4 inch in diameter was measured near Bennett.

In 2000…lightning struck near two golfers at ute creek golf course near Longmont…knocking them to the ground. The men received only minor injuries.

In 2001…lightning from a thunderstorm knocked out electrical power to about 1500 residents in the city of Denver.

In 2004…a chilly day with fog and thunderstorms resulted in two temperature records. The low temperature of 49 degrees was a record minimum for the date. The high temperature of only 58 degrees was a record low maximum for the date.

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.

26

In 1891…a thunderstorm produced sustained northeast winds to 44 mph with gusts to 60 mph and 0.16 inch of rain.

In 1894…a thunderstorm produced sustained southwest winds to 36 mph with gusts to 58 mph…but only 0.04 inch of rain.

In 1910…the high temperature reached 100 degrees in downtown Denver.

In 1959…a Denver man was stunned while standing by a car that was struck by lightning. He was treated for burns and shock at a local hospital. Thunderstorm winds gusted to 55 mph at Stapleton Airport.

In 1983…two heavy thunderstorms hit the northern and western suburbs. The first drenched Northglenn with an inch of rain in 30 minutes. The second storm dumped an inch or more of rain in Idaho Springs and Evergreen. The heaviest rainfall… 2.90 inches in an hour…caused minor street flooding in Golden.

In 1984…heavy early morning thunderstorms drenched the foothills southwest of Denver. Rainfall to 1 1/2 inches in just 30 minutes occurred between Evergreen and Conifer. In nearby Turkey Creek Canyon…1.80 inches of rain was recorded in 35 minutes.

In 1985…a long rope-like white tornado touched down 5 miles east of Erie and stayed on the ground…mainly over an open field…for 18 minutes. However…the twister damaged a few cars on I-25 and injured 3 people from broken glass. The storm flipped over a van…blew out car windows…and ripped a highway sign. It also blew an outbuilding off its foundation. A tornado also touched down briefly 8 miles north of Bennett. No damage was reported from this storm.

In 1988…a 9-year-old girl was slightly injured by lightning in Parker.

In 2003…a severe thunderstorm in and south of Franktown produced hail as large as 1.75 inches in diameter.

Continue reading July 24 to July 30: This week in Denver weather history →

Our weekly look back at Denver weather history always has interesting items but this week one stands out in particular. Denver has never officially recorded snow during the month of July. However, before official records began in 1882, the U.S. Army Signal Service weather observer reported snow on July 17, 1872!

From the National Weather Service:

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.

16-18

In 1997…an extended hot spell resulted in 3 temperature records being set. The maximum temperature reached 98 degrees on each of the days…setting records on the 16th and 18th. The low temperature of 71 degrees on the 17th was a record high minimum for the date. The high temperature reached 100 degrees on the 17th at the site of the former Stapleton International Airport.

17

In 1872…the U.S. Army Signal Service weather observer recorded snowfall during the early morning hours in the hand written daily weather journal: “rain commenced at 1:30 a.m. changing about 3 a.m. to snow & in about half an hour to rain again; it continued until 6 a.m.” this is the only recorded occurrence of snowfall in Denver in July…but this report is not included in the “official” station snowfall records…which did not begin in Denver until January 1…1882. The low temperature on this morning was 45 degrees…which is sufficiently cold for the occurrence of light stratiform snowfall.

In 1918…a thunderstorm produced hail to an inch in depth on the ground. The stones varied in size from a small cherry stone to nearly 1/2 inch in diameter. Not much permanent damage was done to crops. Precipitation totaled 0.40 inch…and northeast winds were sustained to 25 mph with gusts to 28 mph.

In 1971…the temperature reached a high of 101 degrees at Stapleton International Airport.

In 1983…3/4 inch diameter hail fell at Lafayette…while golf ball size hail pelted Brighton and Northglenn where funnel clouds were also sighted.

In 1986…1 1/2 inches of rain fell in an hour and 15 minutes in southeastern Aurora. Thunderstorm rainfall totaled 0.89 inches at Stapleton International Airport.

In 1987…a small tornado was sighted near Watkins…in the vicinity of Front Range airport.

In 1997…lightning ignited an oil well tank holding 10 thousand gallons of oil…16 miles northwest of Bennett. About 200 acres of grassland burned before the fire could be extinguished. A dry microburst produced a wind gust to 52 mph at Denver International Airport.

In 2000…an estimated 2 inches of rain fell in less than an hour…causing two secondary roads in buck and miller gulches in the hi meadows fire burn area to wash out. Water also covered Jefferson County road 68 which connects to Bailey. Homeowners in pine valley estates attempted to divert some of the runoff by piling stacks of hay on the hillside above their homes. Torrential rainfall…up to 3.50 inches an hour…caused flash flooding along Whiskey Gulch near Elizabeth. Several roads were washed out and basements flooded during the storm. Along County Road 13… About 6 miles north-northwest of Elizabeth…rushing water washed away a 15-foot section of the road. The floodwaters forced debris and mud into four huge culverts…sending water over the road. At Denver International Airport…an United Airlines ground crew worker was struck by lightning as she was loading a Boeing 747 jumbo jet. The woman was injured when lightning either hit the jet or the loading equipment that she was working near. The 25-year-old woman received only minor injuries.

In 2006…outflow from severe thunderstorms to the southeast of metro Denver produced southeast sustained winds to 35 mph with gusts as high as 52 mph at Denver International Airport during the late evening.

In 2011…a deluge of heavy rain occurred in and around Nederland when the storm dumped nearly 2 inches of rain in 30 minutes. The heavy rainfall washed out hillsides and dirt roads. In Nederland…a culvert became blocked with debris and forced the water to spread into a nearby bookstore. The rainfall also damaged several residential roads in the Sunnyside Subdivision and Navajo Road became impassable. Several homes suffered flood damage as the runoff from a nearby Beaver Creek jumped its banks and flooded garages…living rooms and bedrooms of nearby houses.

18

In 1874…the temperature climbed to 90 degrees or more for the 18th consecutive day…setting a record. The record was equaled from July 6th through the 23rd in 1901.

In 1902…a thunderstorm produced northwest winds sustained to 45 mph with gusts to 48 mph along with rain and hail. Total precipitation was 0.53 inch.

In 1911…a shower produced north winds sustained to 44 mph.

In 1958…1 1/2 inch diameter hail fell 9 miles west-southwest of Stapleton Airport.

In 1981…a thunderstorm bombed Evergreen with about 2 inches of rain in 45 minutes. A heavy hailstorm left 5 to 7 inches of hail on the ground in some places and stopped the Colorado Open golf tournament at Hiwan.

In 1985…over 2 inches of rain doused the southwest suburbs of Denver. Street flooding occurred in the Montbello area of northeast Denver.

In 1992…nickel size hail fell across central Douglas County near Castle Rock and Sedalia. One inch diameter hail fell in Castle Rock.

In 1993…thunderstorm winds gusted to 60 mph at Strasburg east of Denver.

In 2004…heavy thunderstorm rainfall caused flooding over parts of the Virginia Canyon Road near Idaho Springs. Several sections of the roadway were washed out. The road was closed temporarily for repairs.

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.
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.

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.

19-23

In 2005…the high temperature climbed above 100 degrees on each of the 5 days with readings of 101 on the 19th…105 on the 20th…104 on the 21st…and 102 on both the 22nd and 23rd. A new record maximum temperature for the month of July of 105 degrees was set on the 20th…which also equaled the all time record maximum for Denver of 105 degrees first set on August 8th in 1878. Daily maximum temperature records were set on each day…and the 5 day period equaled the record for the most consecutive days of 100 degrees or more first set from July 4th through 8th in 1989. The intense heat resulted in a high use of electricity for cooling purposes. The demand for electric power exceeded the supply and rolling black-outs… Each lasting about an hour…were scheduled across metro Denver during the afternoons and early evenings.

Continue reading July 17 to July 23: This Week in Denver Weather History →