Weirdest August Weather Ever in Metro Denver

Photo by NOAA on Unsplash
The final numbers aren't in yet, but according to CBS4 Denver forecaster Ashton Altieri, August 2022 is likely to end up as one of the hottest months on the Front Range since 1872, when statistics were first kept — and today's forecast calls for a high of 91 degrees.

Such a record would be in keeping with local weather history, though, since the month of August frequently produces some of the wildest and most extreme weather in metro Denver. For example, there was the day in 1875 when swarms of grasshoppers descended on the city, and the insects were "so numerous as to almost darken the sun."

This information comes from the National Weather Service, whose Boulder-Denver branch has assembled notable episodes from the area's meteorological past for every day of the year — and the ones for August are particularly crazy. Beyond those grasshoppers, which struck during consecutive years in the 1870s, the accounts tell of "great deposits of mud" following a storm that engulfed Denver in a "deadly stench" owing to the number of drowned farm animals; lightning that caused an oil-storage tank to explode, in turn causing forty-foot-high flames to rage for more than an hour; and another lightning strike that injured a man riding a roller coaster.

Here are our picks for the most bizarre weather episodes in the area for each day of August over the past 150 years, with text from the NWS website. The accounts should make you feel better about how much you'll be sweating this afternoon.

August 1, 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.

August 2, 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.

August 3, 1933
Heavy cloudburst rains caused the failure of the Castlewood Dam, which resulted in flash flooding on Cherry Creek, the deaths of 7 people in Denver, and flood damage estimated at 1 million dollars. Lower Denver was flooded during the morning by waters pouring down Cherry Creek and its valley from Castlewood Dam, which had broken between midnight and 2:00 AM. Heavy rain of 3 to 9 inches in 9 hours in the watershed above the dam resulted in the failure. At 7:30 AM, the flow in Cherry Creek was reported at 16 thousand second-feet as compared with a peak flow of 3 thousand second-feet in other years. The flood waters ruined hundreds of acres of crops and drowned scores of farm animals. Six bridges in Denver were swept away. Great deposits of mud were left in the lower sections of the city, including hundreds of basements and lower floors of buildings. At the end of the month, a deadly stench still rose from swampy areas near the lower city limits.

August 4, 1999
Flooding and flash flooding problems developed over metro Denver as slow-moving thunderstorms dumped from 2 to 3.5 inches of rainfall in about 3 hours. Near the junction of I-25 and U.S. Highway 36, up to 4 feet of water flooded an auto dealership. About 45 cars were ruined. Damage estimates to the dealership alone totaled nearly a half million dollars. Sections of I-25 and U.S. 36 near the interchange were closed due to floodwaters. Floodwaters, up to 5 feet deep, forced the evacuation of two mobile home parks in Federal Heights. Railroad tracks were washed out near Federal Blvd. and 64th Avenue. Numerous power outages caused widespread blackouts in Thornton and Littleton. Along Massey Draw near Carr St. and Chatfield Reservoir, 4 homes were flood damaged and portions of their backyards washed out. Widespread street flooding was also reported in Boulder where several buildings were flood damaged, including the University of Colorado Memorial Center.

August 5, 2002
A mail carrier was struck by lightning as he inserted a key into a multi-unit mailbox in Bailey. The shock knocked the man back against the mail truck. He suffered minor injuries. Lightning struck a residence in Commerce City. The resulting fire destroyed the roof of a detached garage and damaged much of its contents. Hail as large as 1 3/4 inches in diameter pelted Pine. One inch diameter hail fell in Arvada and southwest Denver. Heavy rain triggered a mudslide along U.S. Highway 285 near Bailey. Both lanes of traffic had to be closed until debris could be removed from the highway. Several residences in the Bailey and Glenisle areas were also flooded.

August 6, 2008
A record daily rainfall record was set at Denver International Airport. The record of 1.29 inches in 24 hours broke the previous record of 1.10 inches set in 1929.

August 7, 2018
A severe thunderstorm produced large hail around Denver and vicinity. Hail ranging in size from 1 to 1 3/4 inches fell near Firestone, Ft Lupton, Parker, and Smoky Hill.
August 8, 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.

August 9, 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.

August 10, 2015
Heavy rain quickly flooded several intersections in Centennial and vicinity. Vehicles stalled in the flooded intersections. Two motorists had to be rescued from flooded roadways; one at University Blvd. and County Line Road and the other at University Blvd. and Dry Creek Rd. At Centennial Airport, a hangar partially collapsed when 2.17 inches fell in less than 45 minutes. At the Denver Broncos training facility in Dove Valley, the storm left the practice fields and parking lot flooded, and the viewing area near the field house damaged by strong winds. The fields, the team said, received 3.5 inches of rain in an hour during the storm. As a result, the practice facility was closed to the public the following day due to storm damage.

August 11, 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.

August 12, 2004
A brief cool spell resulted in two daily temperature records. The low temperature of 49 degrees was a record minimum for the 12th, as was the low temperature of 48 degrees on the 13th.

August 13, 1983
Thunderstorms dumped torrential rain in Northglenn, Thornton, and Broomfield. Northglenn was drenched with 1.72 inches in 30 minutes. Street flooding was widespread. Hail, as large as 3/4 inch in diameter, was reported 7 miles northeast of Boulder along with heavy rain which caused some street flooding.

August 14, 1977
Three tornadoes were sighted in Bennett. A man suffered a broken leg when hit by a flying board. He was outside his camper home, which was destroyed. All windows were broken in a near-by farmhouse where some shingles were ripped off and a 2 car garage was knocked down. Several vehicles were damaged and a cat, some rabbits, and chickens were killed. A broken oar from a boat was driven into the side of a house. A mobile home was overturned. One old barn was destroyed. Half a dozen homes and several agricultural buildings were damaged just west of State Highway 79.

August 15, 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 and 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.

August 16, 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 women was hit by lightning just north of Denver. A house in the area was also struck.

August 17, 1993
Just west of Fort Lupton, thunderstorm winds blew the tin roof off a cattle shelter into a mobile home, causing considerable damage to the mobile home.

August 18, 2004
Heavy thunderstorm rainfall caused flash flooding across central and southern metro Denver. A rain gauge 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. Floodwaters 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.

August 19, 1875
Grasshoppers appeared in great numbers at 10:00 AM on the 19th and continued through the 30th. 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.

August 20, 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.

August 21, 2019
Severe thunderstorms produced hail up to 1 inch in diameter in parts of Arapahoe, Denver and Jefferson counties. Heavy rain and flash flooding, close to 2 inches in one hour, also accompanied the nearly stationary storms. In Denver, flash flooding caused several vehicles to be stranded at Martin Luther King Blvd. and Dahlia Street. Highway 6 near Federal Blvd. also flooded. Standing water up to 3 feet deep occurred in Park Hill. Lastly, water made its way into buildings north of Interstate 70. At Denver International Airport, just a trace of rainfall was recorded.

August 22, 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.

August 23, 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 vertebra. Another camper narrowly escaped injury. Seconds after he backed up his truck, a tree came down where it had been parked.

August 24, 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.

August 25, 1910
The lowest temperature ever recorded in August, 40 degrees, occurred on the 24th, 25th and 26th, as well as 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.

August 26, 1944
One of the most destructive hailstorms in the city in a decade caused damage estimated at nearly one million dollars. The storm occurred within a period of 10 to 30 minutes, between 2:00 PM and 3:00 PM. The hail varied in size from very small to as large as 1 1/2 inches in diameter. Hail covered the ground to a depth of 5 to 6 inches in some sections of the city. Several people were cut by broken glass. The hail and heavy rain flooded underpasses to a depth of 6 feet, and the occupants of stalled autos had to be rescued. Sewers were unable to handle the sudden amount of water, and water backed up and flooded a number of basements. A few first floors of buildings were flooded. The Water Department had a busy time replacing manhole covers that had been displaced by the water pressure. Trees were stripped, one was severely broken, and telephone lines were downed. Roofs, windows, automobiles, awnings, and gardens were severely damaged. Flowers and gardens in some sections of the city were a total loss. Greenhouses were extensively broken with an estimated 20 carloads of glass shattered. Vegetable and truck crops in and around the city were severely shredded. The next day the American Red Cross was designated by the War Agency to grant any and all priorities needed to obtain materials and supplies to replace and repair the damage. In downtown Denver, the thunderstorm produced 0.95 inch of rain and heavy hail along with sustained northwest winds to 25 mph.

August 27, 1967
A young woman was killed by lightning while horseback riding in the suburbs just west of Denver. Her horse died several hours after the incident. A young man and another young woman were also knocked from their horses by the impact of the lightning and required hospitalization.

August 28, 1968
One man was seriously injured by lightning while riding on a roller coaster at a Denver amusement park. An airline employee was injured when lightning struck a jetliner he was servicing at Stapleton International Airport. A lightning-caused fire did extensive damage to one house and minor damage to several others in the City of Denver.

August 29, 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.

August 30, 2016
An intense thunderstorm produced very heavy rain and hail in Westminster, where radar estimated up to 3.6 inches of rainfall. Several vehicles were stranded in 2 to 3 feet of moving water at the intersection of 72nd Ave. and Pecos St. Street flooding was also reported on U.S. 36 at Pecos St.

August 31, 2020
A worsening drought that started in the spring of 2020 continued through August. The month of August tied with 2011 for the warmest August on record. It also occurred in the middle of the second warmest summer on record. The combination of hot and dry conditions, in addition to critically dry fuels from years of beetle kill, resulted in massive wildfires. The Cameron Peak fire, which became the largest wildfire in the state's history, started on August 13th and continued to burn into October. Smoke from this wildfire in addition to several other large wildfires in Colorado and the West resulted in multiple days of extremely poor air quality. In addition, the air quality in Denver and the entire Front Range had deteriorated severely due to the very warm temperatures and high ozone content, which had spiked significantly. In August, 26 days in the month equaled or exceeded 90 degrees.
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Michael Roberts has written for Westword since October 1990, serving stints as music editor and media columnist. He currently covers everything from breaking news and politics to sports and stories that defy categorization.
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