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August 18 to August 24: This Week in Denver Weather History

Sunday, August 18th, 2019 4:32pm MDT
This week in Denver weather history

August 18 to August 24: This Week in Denver Weather History

Our look back at this week in Denver weather history highlights the extreme weather that can be visited upon us this time of year. Many of the events showcase severe weather more associated with spring than the latter half of summer.

From the National Weather Service:


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.


In 1965…heavy rain in areas south and east of Denver caused some flooding in Littleton and Englewood. Clear creek was running near bankfull…and heavy rain in southwest Denver flooded intersections.

In 1966…a brief very heavy thunderstorm dumped 0.61 inch of rain in just 5 minutes at Stapleton International Airport. Total rainfall from the storm…0.64 inch…fell in just 10 minutes. Half inch diameter hail also fell at Stapleton International Airport. The public sighted funnel clouds 10 to 15 miles south of the airport.

In 1967…hail struck in a strip along the eastern foothills and caused minor damage in Boulder. Hail accumulated to a depth of 4 to 6 inches in Jefferson County just southwest of Denver.

In 1983…one inch to hen egg size hail was reported in Broomfield with golf ball size hail at Northglenn.

In 1990…dime size hail and thunderstorm wind gusts to 50 mph were reported by storm spotters just east of Aurora near the intersection of Mississippi Avenue and Gun Club Road. The hail and strong winds damaged a number of windows in the area.

In 1991…very heavy rain from slow moving thunderstorms dumped up to 3 inches of rain in 20 minutes in the vicinity of Idaho Springs and Central City. Flooding in Idaho Springs forced the closure of the Virginia Gulch Road…which runs from Idaho Springs to Central City. Dirt roads above Central City were damaged or destroyed with the mud being swept onto streets in town. High water in Clear Creek…up to 3 feet above flood stage…washed out a bridge in Idaho Springs. Rock and mud slides forced the closure of I-70 about 1 mile east of Idaho Springs.

In 1997…dry microbursts produced two peak wind gusts to an estimated 60 mph east of Buckley Field.

In 2000…hail as large as 3/4 inch in diameter was measured 5 miles west of Sedalia.

In 2003…a severe thunderstorm produced hail as large as 2.75 inches in diameter at Highlands Ranch. Hail to 3/4 inch was reported in Aurora near Cherry Creek and in Arapahoe County 9 miles southeast of Aurora.

In 2004…heavy thunderstorm rainfall caused flash flooding across central and southern metro Denver. A rain gage at City Park recorded 4.37 inches of rainfall from the deluge. Several roads in and around the city had to be closed due to floodwaters…stranding many vehicles. The Denver fire department conducted at least 15 water rescues. One driver nearly drowned when he made a wrong turn into a retaining pond. Four men who witnessed the accident were able to save the man before his car was completely submerged. Widespread street flooding was reported in the Denver Stapleton area where rainfall totaled 3.81 inches. Standing water over 6 inches deep was reported near I-70 and Quebec…I-225 south of I-70…and I-25 near 6th Avenue. Flood waters reached 8 feet deep in some low lying areas as sewers became clogged and the storm runoff pipes were unable to handle the heavy flow of water. Heavy rainfall caused additional flash flooding south of Denver. Several street intersections in Centennial and southern Aurora became impassable due to high water. Two feet of water covered portions of the roadway near Park Meadows Mall. One person had to be rescued near the intersection of Arapahoe Road and Liverpool. Floodwaters forced the closure of Stonegate Parkway near Jordan Road and Lincoln Avenue. Flooding was also reported on Meridian Blvd. near I-25. Rainfall was 1.62 inches at Denver International Airport.


In 1875…nearly 0.75 inch of rainfall in the city overnight… Possibly assisted by heavier rainfall upstream…produced a decided and rapid rise in Cherry Creek…which washed out some bridges. Other small creeks and streams were filled to overflowing.


In 1983…heavy rain fell across the northern metro Denver suburbs with 1.50 to 1.80 inches of rain in Broomfield… Arvada…and Thornton.

In 1989…lightning killed a 31-year-old man and injured his 10 year old nephew when it hit a tree they were walking under in the foothills about 5 miles west of Boulder. The boy received mouth to mouth resuscitation on the scene and recovered after being hospitalized overnight. Three other people were knocked to the ground by the bolt…but were uninjured.

In 1990…3/4 inch diameter hail was reported in Wheat Ridge. A thunderstorm over west Denver dumped an inch of rain in 20 minutes…causing minor street flooding. One inch diameter hail was reported over east Denver. Ping pong to golf ball size hail was reported 14 miles northeast of Denver at the intersection of 122nd Ave. and Brighton Blvd. The hail stones knocked out windows and did an unspecified amount of damage to the roof of a house. Close by…heavy thunderstorm rains caused gullies…irrigation ditches…and small streams to overflow their banks near the intersection of 120th Avenue and Riverdale Road. Flood waters 1 to 2 feet deep covered the river bottom land along the South Platte River. However…no structures were threatened by the flood waters.

In 1999…heavy rain…up to 5 inches in two hours…caused east tollgate creek to jump its banks. The bike path adjacent to the creek was underwater at several locations. Several underpasses were also flooded…halting traffic. In addition…an unfinished playground at a local elementary school was completely flooded. Lightning struck a vehicle at East Evans Avenue and Tower Road. The woman inside the vehicle was not injured.


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.


In 1980…winds to 55 to 60 mph were recorded in south Boulder.

In 1982…strong thunderstorm winds blasted the Jefferson County Airport near Broomfield…causing an estimated 3 million dollars in damage. At least 5 hangars and 15 airplanes were damaged…many seriously; one hangar was completely destroyed. Torrential rains accompanied the winds. Heavy rains also dumped on Boulder where 1.65 inches fell in just 15 minutes…causing street flooding. Wind gusts to 72 mph were recorded in Boulder. Over half an inch of rain fell in just 5 minutes in Littleton where two homes were struck by lightning. Lightning also struck a house in Arvada where over an inch of rain sent Ralston Creek over its banks. Strong winds accompanied the storms.

In 1984…slow moving thunderstorms dumped 1.25 inches of rain in Evergreen…causing street flooding. A half inch of rain fell in just 18 minutes in southeast Denver. Littleton and Boulder were also drenched with about an inch of rain. Rainfall totaled 0.92 inch at Stapleton International Airport.

In 2001…severe thunderstorms produced damaging winds and large hail across metro Denver. Hail as large 1 inch in diameter fell in Aurora near Cherry Creek. Strong thunderstorm winds gusting as high as 58 mph blew the roof from a building between Thornton and Denver and toppled several trees in Denver. One tree landed on a mail truck. Other thunderstorm winds were clocked to 60 mph near Parker… 62 mph in Broomfield…and 61 mph at Denver International Airport.

In 2006…a tornado (f0) touched down near Bennett…but caused no reported damage.

In 2013…severe thunderstorms pounded the southern Denver suburbs and other parts of the Front Range. In Jefferson County…water rescues were reported for some people in stranded cars. In the Ken Caryl area…large hail from one inch to 1 3/4 inches in diameter was reported. On West Chatfield Avenue in Jefferson County…hail runoff gathered six inches deep in spots and “hail plows” were sent out to clear some streets. Hail up to one inch in diameter was also reported near Castle Rock.


In 1876…heavy thunderstorm rain and hail struck the city. Hail stones as large as partridge eggs accumulated to a depth of 1 1/2 feet over eastern portions of the city. The heavy rainfall flooded streets and gutters. However… No significant damage was reported. Rainfall totaled 0.85 inch in central Denver.

In 1903…a thunderstorm produced west winds sustained to 42 mph with gusts to 48 mph.

In 1957…heavy thunderstorm rainfall and hail over the bear creek basin flooded portions of State Highway 8 in and near Morrison. There was also minor property damage in Morrison.

In 1995…a 68-year-old woman was struck by lightning while standing near a tree in Brighton.

In 2006…a severe thunderstorm produced 7/8 inch diameter hail in Franktown.


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.


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.


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 escape several falling trees in his ATV. One of the trees struck his back and broke two vertebra. Another camper narrowly escaped injury. Seconds after he back up his truck…a tree came down where it had been parked.


In 1880…a thunderstorm produced vivid lightning and heavy rainfall…which caused flooding over the eastern part of the city including the brick yards. There was no rainfall recorded in downtown Denver.

In 1910…an apparent dry cold front caused a remarkable drop in temperature. From 3:00 pm until midnight the temperature fell from a high of 93 degrees to a low of 40 degrees. Northeast winds were sustained to 44 mph during the late afternoon.

In 1946…heavy rain near Idledale caused flooding on bear creek at Morrison…which resulted in one death when a woman was swept from her stranded car and drowned.

In 1973…strong winds blew down a few power lines and hail up to 3/4 inch diameter fell in southeast Aurora.

In 1984…heavy rain hit the south Denver area. Over an inch fell in less than an hour at both Castle Rock and Sedalia.

In 1992…heavy rains caused flash flooding across parts of metro Denver. Rainfall amounts of 1 to 3 inches fell with the hardest hit areas being the southwest and central parts of metro Denver. Bear creek rose above bankfull near Idledale with flood waters moving into southwest metro Denver. Mud and rock slides along Colorado Highway 74 west of Morrison were reported. The confluence of Cherry Creek and the South Platte River in downtown Denver also went out of its banks…flooding bike paths. Rainfall totaled 1.98 inches at Stapleton International Airport where light to moderate rain fell most of the day. Heavy rain and fog briefly reduced the surface visibility to 1 1/2 miles. The temperature climbed to a high of only 58 degrees…which was a record low maximum for the date.

In 2002…hail to 7/8 inch in diameter was measured in southwest Denver.

In 2008…several landspout tornadoes developed along a boundary to the southeast of the Denver metropolitan area during the Democratic National Convention. In northwest Elbert County… Minor damage was reported. The damage consisted of downed power lines…broken windows and an out building. Severe thunderstorms also produced very heavy rain and large hail… Up to one inch in diameter. In southwest Douglas County… Heavy rain caused flash flooding near the town of Westcreek. A mudslide closed State Highway 67. The road in the YMCA Camp Shady Brook was also washed out and some bridges were damaged.


In 1910…the lowest temperature ever recorded in August…40 degrees…occurred on each of these days and on August 22… 1904. The unusually cold weather for so early in the season brought sub-freezing minimum temperatures to much of the Colorado northeastern plains.

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