The beginning of August typically continues our monsoon season. This leads to increased chances for thunderstorms with heavy rain and the associated hazards that come with it. Our look back at this week in Denver weather history highlights the dangers of flooding, hail and lightning and even includes reference to grasshopper swarms being blown into the city.

From the National Weather Service:

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In 1988…two inches of rain fell in 3 hours at both Morrison and Wheat Ridge. Thunderstorm rainfall totaled 0.80 inch overnight at Stapleton International Airport.

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In 1889…southwest winds were sustained to 42 mph with an extreme velocity to 52 mph.

In 1924…0.01 inch of rain fell over downtown Denver. This along with the 0.01 inch of rainfall on the 10th was the only rainfall of the month…the driest August on record.

In 1963…heavy rains in the foothills above Idaho Springs caused mud and rock slides which closed U.S. Highways 6 and 40 for a time.

In 1976…hail to 1 inch diameter was reported 12 miles southwest of Denver. Hail to 3/4 inch in diameter was reported in Lakewood. Small hail…1/4 to 1/2 inch in diameter…fell at Stapleton International Airport.

In 1982…heavy rain poured through the roof of a clothing store in Aurora…causing widespread water damage. The roof was being repaired when the storm hit.

In 1983…hail up to one inch in diameter fell in Aurora where heavy rain produced street flooding.

In 1984…a Colorado state trooper was struck and injured by lightning in Northglenn.

In 1989…a microburst wind gust to 52 mph was recorded at Stapleton International Airport.

In 1997…lightning sparked a small fire in a home in Arvada… Causing minor damage. Several intersections in both Arvada and Westminster were flooded by thunderstorms producing heavy rain. Several cars were damaged by the high waters… And a number of businesses were flooded.

In 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.

In 2004…two golfers were shocked when lightning struck the eighth green of the golf course at Castle Pines north of Castle Rock. The two men suffered only minor injuries. Heavy thunderstorm rain from the same storm caused flash flooding. Floodwaters rushed across parts of U.S. Highway 85 near the entrance to the Castle Pines Golf Club. The traffic lanes were covered with up to 6 inches of running water.

In 2008…lightning sparked a grassfire that consumed 300 acres on the northern edge of Green Mountain…in Jefferson County. Gusty winds and very dry conditions allowed the wildfire to quickly spread and threaten several houses. Fortunately…only minor damage was reported to homes due to smoke and melted siding.

In 2018 a severe thunderstorm produced strong winds in and around Denver. A peak wind gust to 60 mph was observed near Firestone with a gust to 59 mph near Buckley Air Force Base. A peak wind gust to 40 mph from the southwest was observed at Denver International Airport.

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In 1881…the low temperature cooled to only 76 degrees…the record high minimum temperature for the month.

In 1889…southwest winds were sustained to 42 mph.

In 1918…hail pelted the city…but was light and caused no damage. Precipitation totaled 0.25 inch. Northwest winds were sustained to 31 mph.

In 1964…lightning struck two boys in Denver while playing ball. One was treated and released from the hospital…but the other boy suffered second degree electrical shock and cardiac arrest and was hospitalized in critical condition for several days.

In 1969…two tornadoes touched down briefly in an open field southeast of Buckley Field in Aurora. No damage was reported.

In 1970…heavy rain in the Indian Hills area in the foothills west of Denver caused flash flooding…which washed out roads and damaged other property. Hail accumulated to a 3 inch depth with stones up to golf ball size; however…most of the damage was from flooding.

In 1982…2.38 inches of rain fell in an hour in Arvada… Causing minor flooding on Ralston Creek. In Westminster… 1 1/2 inches of rain fell…causing damage to streets and culverts. In addition…lightning caused some minor power outages across metro Denver.

In 1983…very heavy thunderstorms hit the southern portion of metro Denver. Heavy rainfall…as much as 2.89 inches in 38 minutes…caused widespread street flooding in southeast Denver. Two feet of water covered a section of I-25. Hail up to golf ball size accompanied the storm in Littleton and Englewood…along with 60 mph winds.

In 1984…a heavy thunderstorm drenched Littleton with up to 2.35 inches of rain in an hour…along with small hail that piled up to 2 inches deep. Flood waters were up to 4 feet deep in parts of town with many basements flooded. There were some power outages caused by lightning.

In 1990…a thunderstorm dumped 1.25 inches of rain in 12 minutes near tower and smoky hill roads in southeast Aurora. Minor street flooding was reported in the area.

In 1992…a pilot reported two funnel clouds near Cheery Creek Reservoir. Both dissipated quickly. Dime size hail fell near Franktown.

In 1994…one inch diameter hail fell near Strasburg. No damage was reported.

In 1999…a dog kennel east of Denver International Airport… Was flooded when a small dam…upstream in Elbert County… Was breached. The floodwaters…up to 4 feet deep…washed away some 6-foot fences and other small buildings. Ten of the 70 dogs boarded at the kennel drowned.

In 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.

In 2004…heavy thunderstorm rainfall caused localized flash flooding in Virginia Canyon near Idaho Springs. Sections of the Virginia Canyon Road had to be closed due to the floodwaters.

In 2008…a severe thunderstorm produced large hail…up to 1 1/4 inches in diameter…northeast of Parker. Several automobiles were damaged.

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In 1877…a severe rain…hail…and wind storm struck Denver. The storm produced a one minute sustained wind speed of 75 mph. Rainfall totaled 1.00 inch in 25 minutes. The hail storm damaged vegetable gardens in the city.

In 1954…an unconfirmed tornado was reported in Westminster. A funnel cloud was sighted in the area…but it was not certain if it had touched down. No damage was reported.

In 1980…the temperature reached 100 degrees…setting a new record high for the date.

In 1982…3/4 inch diameter hail was reported in north Denver. Heavy rain caused street flooding in central Denver where 4 to 5 feet of water inundated I-25…closing the freeway for a while. Rainfall across metro Denver ranged up to 2.35 inches in just over an hour. An estimated 2000 basements were flooded. Only 0.01 inch of rain fell at Stapleton International Airport.

In 1991…heavy rain caused flooding at the junction of I-25 and I-70. Dime size hail was reported northeast of Boulder near Niwot.

In 1995…microburst winds gusting as high as 58 mph caused minor damage to an apartment complex in Broomfield. Some homes under construction were also damaged when the winds knocked over 2 by 4 wood beams along with some insulation and roofing materials…which broke a few windows. Microburst winds also overturned a camper near Barr Lake.

In 1996…hail ranging in size from 1 to 1 1/2 inches fell near Bennett.

In 2001…3/4 inch hail fell in the foothills near Conifer.

In 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.

In 2020…a severe thunderstorm developed near Byers. The wind snapped large tree branches…up to 4 inches in diameter…and produce large hail up to one inch in diameter. At Denver International Airport…a peak wind gust to 47 mph was observed from the west.

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In 1948…a brief west moving tornado was sighted 3 miles north-northeast of Stapleton Airport. The white funnel silhouetted against a gray cloud background was very narrow…nearly vertical…and estimated at nearly 5 thousand feet high. A dust cloud formed on the ground around the funnel. No damage was reported.

In 1952…a thunderstorm wind gust to 52 mph was recorded at Stapleton Airport.

In 2014…severe thunderstorms produced large hail across western and southern parts of metro Denver. Near Centennial and Golden…hail up to quarter size was reported. Near Bennett…a peak thunderstorm wind gust to 65 mph was also reported. At Denver International Airport…a peak wind gust to 46 mph was recorded.

In 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.

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

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

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

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

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

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

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

In 2013…heavy rain caused localized flash flooding in Aurora. An undergound parking garage at an apartment complex was inundated with 3 to 4 feet of water. Flash flooding forced a road closure at East Mississippi Ave. and Alton St. Also… several people had to be rescued when three vehicles stalled in floodwaters at Alameda Ave. and Havana St. The stationary thunderstorms dumped 2.75 inches of rain in less than 45 minutes. In addition…large hail…up to one inch in diameter… was reported north of Roxbourough State Park. At Denver International Airport…just a trace of rainfall was observed.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

In 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; on at University Blvd and County Line Road and the other…at Univerity 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.