August is usually considered one of the calmer weather months in Denver but as our look back in weather history for this week shows, that isn’t always the case.  Thunderstorms and all their associated dangers – lightning, flooding, tornadoes and more – all present a very real danger even this time of year.

From the National Weather Service:

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In 1902…a thunderstorm produced west winds sustained to 48 mph with gusts to 60 mph…but only a trace of rain.

In 1952…a thunderstorm wind gust to 50 mph was recorded at Stapleton Airport.

In 1960…lightning struck a warehouse in central Denver… Causing 8 thousand dollars in damage to the building and stored electrical equipment.

In 1975…large hail…1 1/2 to 1 3/4 inches in diameter…fell about 4 miles north of Castle Rock.  Hail caused some minor damage in Aurora.  A funnel cloud was reported 25 miles east of Denver near Bennett.

In 1981…a tornado touched down briefly in open country just to the east of Aurora.  No damage was reported.

In 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.

In 1985…a thunderstorm produced strong wind gusts over southern metro Denver.  One strong wind gust hit Cheery Creek Reservoir…capsizing a boat and drowning a man.  The wind gusts…clocked as high as 50 mph…also downed a few trees.

In 1989…1 3/4 inch diameter hail fell at Intercanyon in the foothills of Jefferson County.

In 1990…lightning caused minor damage to a south Aurora home.  No injuries were reported.

In 1994…strong thunderstorm winds caused damage in southern Weld County near Hudson and Fort Lupton.  Two mobile homes were destroyed and a few lost their roofs.  Up to 20 downed power poles and the destruction of two 115 thousand-volt towers caused widespread power outages.  Thunderstorm gust front winds from the north gusted to 48 mph at Stapleton International Airport.

In 2000…lightning ripped most of the roof from a home in southeast Aurora.  The bolt sparked a fire which destroyed the residence.  Damage was estimated at 250 thousand dollars.

In 2002…the temperature climbed to a maximum of 100 degrees setting a new record high for the date.

In 2003…a teenager was injured when he was struck by lightning while camping at Herman Lake…13 miles northwest of Georgetown.  The boy was knocked unconscious and suffered minor injuries.

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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.

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In 1953…a tornado was sighted 8 miles east of Castle Rock. An unconfirmed tornado was sighted between Denver and Strasburg.  No damage was reported.

In 1963…heavy rain in southeast Denver…Englewood…and Littleton caused flooding of basements and streets.  Over 3.00 inches of rain fell at Cherry Creek Dam.  Lightning caused power failures.  The hardest hit areas were in north- central Denver.  A 12-year-old boy was swept into a conduit by a 3-foot high crest of water.  He was carried 125 feet through the waterway…but was unhurt.  Thunderstorm rainfall totaled only 0.24 inch at Stapleton Airport.

In 1972…a thunderstorm wind gust to 53 mph was recorded at Stapleton International Airport.  Strong winds also occurred in the Littleton area where several trees and utility poles were blown over and a number of windows broken.

In 1978…1 3/4 inch diameter hail was reported in Thornton.

In 1982…heavy rain occurred in the foothills southwest of Denver where 4.50 inches fell in 75 minutes between Evergreen and Conifer.  Nearby…2.66 inches of rain drenched the North Turkey Creek Canyon area in just 15 minutes.

In 1984…scattered slow moving thunderstorms dumped heavy rain across southern metro Denver.  The heavy rain caused some road washouts in Jefferson and Douglas counties.  A bridge was washed out in Douglas County.  Three inches of rain fell in just an hour at Castle Rock…causing heavy silt damage to a home and to nearby drainage ditches.

In 1988…a thunderstorm dumped 2 to 3 inches of rain in southeast Denver and adjacent areas of Arapahoe County in less than 90 minutes.  There was widespread street flooding…and I-25 was closed by 4 feet of water near its intersection with I-225 just south of Denver.  A flood control project in Arapahoe County at greenwood village sustained over 10 thousand dollars damage.  Up to 4 feet of water flooded some basements in the area.  Only 0.44 inch of rain fell at Stapleton International Airport.

In 1990…heavy thunderstorm rains over the Boulder creek and St. Vrain creek drainage basins caused many creeks and drainage ditches to rise in eastern Boulder and southwest Weld counties.  The high waters punched three 30-foot holes in the embankment of a drainage ditch…which traversed through the town of firestone…20 miles north of Denver. A sheet of water 2 to 3 feet deep rushed out onto the streets of firestone…forcing the evacuation of a trailer park and residents from 50 neighboring homes.  No injuries or serious damage occurred except for mud and water damage. Lightning struck and injured 4 construction workers standing in an Aurora field.  They received treatment for minor injuries at a local hospital.  Lightning also struck the roof of a Methodist church in central Denver… Knocking down the highest peak of the steeple.  A half dozen people were in the building…but no one was injured. Slow moving thunderstorms dumped 2 to 3 inches of rain over southeast Aurora in 90 minutes.  The heavy rain accumulated on the roof of a condominium clubhouse…causing the roof to collapse under the weight of the water.  Nearly 300 residents were evacuated from the 200-unit complex because of the structural damage.  The residents were allowed to return to their homes when it was determined the damage was confined to the clubhouse.  No injuries were reported.

In 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.

In 1997…lightning struck a home in Castle Rock sparking a fire.  Damage was estimated at 20 thousand dollars.

In 2000…thunderstorms producing very heavy rain…up to 3.50 inches in spots…caused flooding and flash flooding across metro Denver.  In Commerce City…a 37-year-old firefighter drowned while attempting to rescue a stranded motorist on a flooded street.  The firefighter was wading through the water when he lost his footing and was sucked into a 10 foot deep culvert.  He was swept away before anyone could reach him.  Extensive flooding was also reported throughout Littleton and north Denver.

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

Denver and Colorado as a whole are known for their unusual weather.  This week in particular is notable for one extraordinary event in weather history – clouds of grasshoppers!

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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.

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In 1872…fog was very dense until about 8:00 am.  There was water dripping from the roofs of houses as if it had rained. The rain gage showed 0.01 inch of moisture…even though there had been no rainfall.

In 1927…an apparent dry microburst produced only a trace of rain and brief northwest winds sustained to 34 mph with gusts to 44 mph.

In 1980…hail up to golf ball size caused some roof and car damage in the southern part of Aurora.

In 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.

In 1992…dime size hail fell in Westminster.

In 1994…strong thunderstorms produced large hail across northwest and north metro Denver.  One inch diameter hail fell in Brighton with 3/4 inch hail reported in Westminster and at Indian Hills in the foothills west of Denver. Lightning struck a house in Arvada.  The resulting fire destroyed one-third of the house.  Funnel clouds were sighted over Westminster.

In 1997…large hail…strong winds…and torrential rains hammered portions of Lakewood and south Denver.  Nearly 1 inch of rain fell in the span of 10 minutes in south Denver with a storm total of 1.81 inches.  Street flooding was extensive as gutters and other drainage systems in the area were clogged by hail…piled several inches deep…and other debris.  Strong thunderstorm winds to 50 mph and large hail accompanied by heavy rain caused extensive damage to cars…homes…and businesses.  Several trees were downed by the strong winds…and trees were stripped of their leaves by hail.  A water lily exhibition on display at the Denver botanic gardens was heavily damaged.  Final estimates of the damage included 60 million dollars to automobiles and an additional 68 million dollars to homes and businesses.  Hail to 1 1/2 inches in diameter fell in south Denver with 3/4 to 1 inch hail in Lakewood.  A man received minor injuries in Aurora when he was struck by lightning while talking on the telephone.

In 2003…hail to 3/4 inch in diameter was measured in Aurora near Cherry Creek.

In 2012…a severe thunderstorm produced a wind gust to 60 mph at Rocky Mountain Metropolitan Airport

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In 1876…the temperature climbed to a high of 100 degrees in downtown Denver.

In 1941…excessive thunderstorm rainfall flooded streets and delayed traffic for a few hours in some sections of the city.  The basements of a considerable number of homes and commercial buildings were flooded.  The total value of the damage was unknown.  Only 0.94 inch of thunderstorm rainfall was recorded downtown.

In 1969…a man and a 9-year old boy were injured…when lightning struck a tree near where they were standing. Both were revived after treatment…but the boy later died of respiratory failure due to electrical shock.

In 1984…heavy thunderstorm rains drenched southern metro Denver.  Rural roads in Douglas County received minor washouts.  Hail…as large as 3/4 inch in diameter…was reported in southeast Aurora with one inch diameter hail reported near Parker.  Rainfall totaled 1.00 inch at Stapleton International Airport.

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In 1975…heavy rains caused flash flooding along the foothills from Denver north.  Thunderstorm rainfall totaled 1.56 inches at Stapleton International Airport.

In 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.

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In 1959…thunderstorm winds gusted to 53 mph at Stapleton Airport.

In 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.

In 2000…lightning sparked 3 small grass fires near Golden. The fires were quickly contained.  Hail as large as 3/4 inch in diameter fell in Castle Rock.

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In 1960…a bolt of lightning struck a man in Henderson… Causing serious burns.

In 1962…the temperature climbed to a high of 100 degrees at Stapleton Airport.

In 1968…a young man on a golf course in Denver was injured when lightning struck a tree under which he was standing. Lightning caused minor damage to a house in Denver.  Heavy thunderstorm rain caused local street flooding.  One inch diameter hail fell at Jefferson County airport near Broomfield.

In 1973…winds as high as 85 mph damaged 20 aircraft at the Arapahoe County airport…now Centennial Airport.

In 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.

In 1978…high winds produced much blowing dust…causing many traffic accidents in the Denver-Boulder area.  Winds gusts of 70 to 101 mph were recorded.  Northwest winds gusted to 44 mph at Stapleton International Airport.

In 1980…lightning hit two power poles in Littleton…causing 400 dollars in damage.  Rainfall of 1.23 inches in a short time caused minor flooding…which included damage to a ground floor apartment and partially submerging a few vehicles in water.  Thunderstorm rainfall totaled 0.98 inch at Stapleton International Airport.

In 1983…2.10 inches of rain drenched Golden in an hour with similar amounts in Lakewood and Boulder.  Over ten thousand dollars worth of plants were washed away at a nursery in Lakewood.

In 1997…twelve motorists were injured in a multi-car accident when strong microburst winds estimated to 50 mph blew blinding dust across I-70 near Bennett.

In 1998…lightning struck a hydro-electric plant in Nederland… Causing a power outage.  Residents in the foothills west of Boulder…including Nederland…Ward…Eldora…Jamestown… And Gold Hill…were without power for about an hour.

In 2006…heavy thunderstorm rainfall near Deckers washed away some the banks along State Highway 67 between Deckers and Westcreek.  Several driveways on both sides of the highway were also damaged.

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In 1899…a thunderstorm produced southwest sustained winds to 43 mph with gusts to 46 mph.

In 1972…a pilot reported a funnel cloud briefly touching the ground in open fields…17 miles east-northeast of Stapleton International Airport.

In 1980…thunderstorm winds gusted to 55 mph in Boulder.

In 1982…brief heavy rain and winds estimated as high as 70 mph occurred in the Conifer-Evergreen area.  No damage was reported.

In 1990…lightning triggered a small attic fire in a house near Sedalia…20 miles south of Denver.  A furious lightning storm caused widespread power outages across southern sections of metro Denver.  One lightning bolt knocked out an electrical substation…causing a 90-minute blackout in southeast Denver affecting nearly 10 thousand homes and businesses.

In 2007…severe thunderstorms produced large hail…up to 2 inches in diameter…near larkspur.   Extensive damage to vehicles in the area was reported.  In Parker…lightning struck a residence.  The ensuing fire damaged the attic and top floor; causing $100…000 in property damage.

In 2008…at least three homes were hit by lightning during the early morning hours in Arapahoe County.  Lightning also struck two homes in Castle Rock…damaging the roofs.

In 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 with 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.