We are getting closer to Colorado’s severe weather season and see how dangerous it can be when we look back in Denver weather history.  Many occurrences of dangerous lightning, large hail, flooding and tornadoes have been the hallmark of this week in Denver weather history.

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In 2002…lightning sparked a wildfire near Deckers.  Extremely dry conditions and very strong winds the following day allowed the fire…known as the schoonover…to consume 3850 acres before it could be contained.  Thirteen structures were destroyed…including 4 homes…resulting in 2.2 million dollars in damage.

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In 1876…snow changed to heavy rain over the city…resulting in widespread flooding along Cherry Creek and the South Platte River…nearly as great as the flash flood of May 19-20…1864.  However…damage was greater because the city had grown much larger and there were more bridges for the flood waters to destroy.  Precipitation in the city totaled 6.70 inches from 10:00 pm on the 21st through 3:00 am on the 23rd.  The greatest precipitation ever recorded in Denver in 24 hours…6.53 inches…occurred on the 21st and 22nd.  Small buildings and bridges along Cherry Creek were washed away by the flood waters.  Bridges over the South Platte River were damaged.  The city irrigation ditch was damaged and rendered unfit for service.  Strong winds at speeds of 30 to 40 mph drove the heavy rain through brick walls 12 to 16 inches thick.  Many sheep and cattle were either killed by lightning or drowned…including some 100 head of cattle in Jefferson County alone.  There was immense damage to railroad tracks…especially the Kansas Pacific line to the east of the city.  The Colorado Central suffered estimated damage of 10 to 15 thousand dollars.  In addition…the heavy rain caused extensive flooding on soda and bear creeks in the foothills.  Flooding along Boulder creek inundated farm and pasture land in the Boulder valley and damaged a few bridges.  Rail travel had to be suspended in the area for several days.

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In 1933…high winds and gales overnight caused considerable damage in and near the city.  Much greenhouse glass was broken…which caused damage to sheltered plants.  Great numbers of plants growing in the open were damaged or killed by wind-driven sand and soil.  Fields were eroded by the wind and a few trees were uprooted.  West winds were sustained to 38 mph with gusts as high as 65 mph in downtown Denver on the 22nd.

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In 1916…southeast winds were sustained to 43 mph with gusts as high as 52 mph.  The winds were strong for several hours during the afternoon.

In 1965…thunderstorm outflow wind gusts to 59 mph were recorded at Stapleton International Airport.

In 1987…slow moving thunderstorms bombarded metro Denver. One inch diameter hail was reported in south central Denver.  Torrential rain caused widespread street flooding… Stalling traffic throughout the area.  Rainfall totaled 2.10 inches in just 25 minutes in extreme southeast Aurora. Many other locations in Aurora and east Denver reported 1 to 1 1/2 inches of rain in about 30 minutes.  Thunderstorm rainfall totaled 1.33 inches at Stapleton International Airport where 1/4 inch diameter hail was measured and north winds gusted to 40 mph.  A man was slightly injured by lightning near Stapleton International Airport.  Lightning also started a fire that severely damaged a house in Aurora.

In 1990…a microburst wind gust to 52 mph at Stapleton International Airport produced some blowing dust.

In 1991…thunderstorms moving from southwestern sections of metro Denver to the east of Denver produced large hail up to golf ball size.  An estimated 5 thousand homes and 8 thousand cars received considerable damage.  Early estimates placed damage costs around 60 million dollars. Three funnel clouds were also reported…two by personnel at Buckley Field and the other by a storm spotter.  Heavy rain produced street flooding in Aurora where hail accumulated to a depth of 6 inches.  As the storms moved to the east…golf ball size hail was reported at Strasburg.

In 1997…hail to 3/4 inch diameter fell in Broomfield.

In 2002…a very strong microburst near Strasburg swept a woman into a swirl of dirt and carried her about 150 feet. The woman was in an open field…corralling a yearling horse… When the incident occurred.  Fortunately…she received only minor injuries.

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In 2002…a pacific storm system brought much needed snow to the mountains and foothills with a mix of rain and snow on the plains.  The most snow fell from central Jefferson County northward.  Snow totals included:  13 inches in Coal Creek Canyon…11 inches near Evergreen and atop gold hill… 10 inches near Blackhawk and conifer and atop Crow Hill… 9 inches near Rollinsville…and 8 inches near Genesee and Golden.  Rain was mixed with snow across the city. Precipitation totaled 0.61 inch at Denver International Airport.  Snowfall was less than an inch at the site of the former Stapleton International Airport.  The storm brought unseasonably cold air to metro Denver.  Three temperature records were set.  Low temperature of 31 degrees on the 23rd was a record minimum for the date…as was the low of 32 degrees on the 24th.  The high temperature of only 48 degrees equaled the record low maximum for the date.

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In 1953…a microburst caused a brief wind gust to 55 mph at Stapleton Airport.

In 1957…walnut size hail…1 1/2 inches in diameter…fell in east Denver.  Only 1/4 inch hail was measured at Stapleton Airport.

In 1958…rainfall totaled 1 to 2 inches across metro Denver. Rainfall was only 0.37 inches at Stapleton Airport.

In 1974…a tornado was observed briefly near Watkins.  No damage was reported.

In 1980…strong gusty winds of at least 60 mph damaged buildings in parts of Denver.  Several buildings were unroofed in Sheridan.  The flying debris damaged other structures.  Strong microburst winds gusted to 52 mph at Stapleton International Airport.

In 1991…a tornado touched down briefly in open country near Bennett.  No damage was reported.

In 1994…weather spotters reported 2 funnel clouds over Aurora and a short-lived waterspout on Cheery Creek Reservoir.

In 1997…hail to 1 inch in diameter fell in Broomfield with 3/4 inch hail measured in Boulder.

In 1998…a tornado struck a wooden hangar at the Aurora airpark.  The hangar collapsed…damaging a car and a single engine plane parked inside.  An adjacent steel hangar sustained only minor damage.  The tornado moved northeast…hopped I-70…and touched down again in an open field.  Earlier…a weak tornado touched down briefly in an open field 10 miles southeast of Buckley Field.

In 2003…severe thunderstorms produced large hail over northern and southern metro Denver.  Hail as large as 2 3/4 inches in diameter was measured 10 miles northwest of Hudson and to 2 inches in diameter 10 miles northeast of Fort Lupton.  One inch diameter hail fell in Fort Lupton.  Hail to 1 inch in diameter fell near Parker and to 3/4 inch near Franktown.

In 2004…severe thunderstorms moved across northwest and north metro Denver.  Hail as large as 1 inch in diameter fell in Broomfield and Thornton with 3/4 inch hail measured near Arvada and Hudson and in the city of Denver.

In 2005…severe thunderstorms produced hail as large as 1 inch in diameter in Arvada and the city of Denver.

In 2014…a severe thunderstorm in Lakewood produced hail… up to 1 inch in diameter.

In 2016…a long-lived supercell formed over south Denver and tracked across northeast Adams and continued to produce severe weather as into moved into Yuma County. The length of its path was approximately 121 miles. The storm produced hail up to 1.5 inches in diameter in southeast Denver. As it moved across northeast Adams County…several power poles were sheared off at the base by straight-line winds to 80 mph southwest of Leader. The damage path became more extensive as the storm moved into the northeast plains of Colorado. At Denver International Airport…1.15 inches of precipitation fell which set a new daily precipitation record. The storm produced heavier rainfall on one to two inches east of Denver…with over 4 inches in central Arapahoe County.

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In 1996…a late spring snowstorm dumped 4 to 10 inches of snow over the Front Range foothills.  Conifer picked up 10 inches of new snow; Aspen Springs…9 inches; and central city…8 inches.  The sticky…heavy snow clung to power lines and pulled tree branches down…causing power outages to about 1200 homes in the conifer area.  It took up to 6 hours to restore power to some residences. Lightning struck a telephone data cabinet in conifer on the 25th…which knocked out phone service to about 1500 customers.  Widespread rain fell across metro Denver… Where rainfall totaled 2.07 inches at the site of the former Stapleton International Airport and 1.66 inches at Denver International Airport where north winds gusted to 24 mph on the 26th.

In 2010…from the 24th to the 26th…high winds preceding a cold front…swept across the Front Range Foothills and Urban Corridor.  In Aurora…the wind damaged the roof of Rangeview High School.  In Conifer and Denver…the wind downed trees and power lines and caused several brief outages.  The downed power lines also caused several cars to catch fire in the vicinity of 1590 Cook St. in Denver. Peak wind gusts included:  82 mph at Highlands Ranch…67 mph…4 miles east of Franktown and Longmont; 65 mph in Boulder…64 mph in Centennial and Denver International Airport…62 mph near Parker and 60 mph in Arvada.

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In 1877…lightning killed one person in west Denver and struck several houses.  The bolt struck the house of the “home laundry” stunning the occupants and killing a lady who was holding one of her grand children in her arms. The child escaped unhurt.  The lightning also struck the top of a tree in front of the house and partially peeled the bark off the tree.  Lightning struck a church in the Evans addition and another tree in east Denver.  Lightning struck the switch room at the telegraph office where the operator saw small balls of lightning pass across the room to the stove.  The thunderstorm pelted the city with only pea size hail.  Precipitation from the storm totaled 0.40 inch in downtown Denver.

In 1880…light rain all afternoon totaled only 0.24 inch in the city…but was valuable to stockmen and farmers due to the very dry…parched weather conditions on the plains.

In 1965…a tornado was sighted by a pilot 30 miles south southeast of Denver.   No damage was reported.  Another pilot reported 3/4 inch hail 30 miles east of Denver.  The state patrol reported that a man was killed when a fierce gust of wind swept him from the back of a pick-up truck in northwest Douglas County.  The man was holding a mattress in the bed of the truck.

In 1974…a microburst wind gust to 53 mph was recorded at Stapleton International Airport.  A pilot reported a tornado 20 miles east of Denver.

In 1976…lightning struck a home in Boulder…shattering 2 large trees and damaging a television set.

In 1997…hail as large as 1 3/4 inches in diameter fell near Watkins.  Hail to 3/4 inch in diameter fell in Broomfield and near Lochbuie.

In 2000…3/4 inch diameter hail fell at Cheery Creek Reservoir in Aurora.  Thunderstorm winds gusted to 51 mph at Denver International Airport where small hail fell.

In 2006…a severe thunderstorm produced an estimated wind gust to 70 mph in Hudson.  The strong winds damaged the roof of a home.  A thunderstorm produced southwest wind gusts to 54 mph at Denver International Airport.

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In 1950…a major storm dumped 10.0 inches of snowfall downtown and 10.7 inches at Stapleton Airport where northwest winds gusted to 30 mph on the 25th.  The storm caused extensive damage to utility wires and trees which were in full leaf.  A daily record minimum temperature of 31 degrees occurred on the 25th.  This was the coldest temperature on this date in 79 years and for so late in the season.

In 1989…a late season snow storm dropped snow as low as 6 thousand feet along the Front Range.  Most places in the foothills had 2 to 5 inches of snow.  Overnight rainfall totaled 0.33 inch at Stapleton International Airport where north winds gusted to 37 mph on the 25th.

In 1994…lightning struck a television transmitter on Lookout Mountain near Golden and burned out a switcher…which disrupted cable service for 2 hours.

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In 1897…apparent post-frontal north winds were sustained to 42 mph with gusts as high as 48 mph.

In 1942…the all-time highest recorded temperature in May…95 degrees…occurred.

In 1978…two children were struck and killed by lightning on a junior high school playground in Parker.

In 1987…1 inch diameter hail fell near Boulder and Bennett.  The hail was fairly soft and caused no damage.

In 1993…dry thunderstorms produced wind gusts to 81 mph at Jefferson County Airport near Broomfield.  Several trees were blown down by the strong winds.  Microburst winds gusted to 51 mph at Stapleton International Airport.

In 1995…a woman was injured in Littleton when the car she had just entered was struck by lightning.  All of the windows in the car were blown out by the strike.  A funnel cloud was sighted near Littleton.

In 2000…a strong microburst wind gust to 92 mph flipped a small airplane on its back and blew a DC-3 loose from its moorings…which allowed it to roll onto a grassy field at Front Range Airport near Watkins.

In 2010…severe thunderstorms pounded parts of the Urban Corridor with very large hail…heavy rain…damaging winds and a tornado.  The hail…ranging in size from 1 inch to 2 3/4 inches in diameter…struck Brighton…Commerce City and northeast Denver the hardest. The storms continued to spread destruction to the north and east…impacting Byers…Hudson…Deer Trail and Prospect Valley.  The combination of hail and wind stripped the bark and branches from trees.  Numerous accidents were reported as the hail accumulated up to a foot deep.  Snowplows were called out to clear the roadways.  Flash flooding occurred along State Highway 52 between Hudson and Keenesburg…and forcing the closure of the highway. Widespread crop damage was also reported as the area was inundated with up to 18 inches of water.  Extensive damage to homes…businesses and automobiles was reported with the damage estimated to be around 70 million dollars.  A tornado touched down near Denver International Airport…but did no damage.  Lightning struck a child in Commerce City while she was watching television.  She suffered minor injuries to her leg. At the Rocky Mountain Arsenal Wildlife Refuge…a lightning strike killed a bison.  At Denver International Airport…only 0.01 inch of rainfall was observed…along with a peak wind gust to 48 mph from the southeast.

In 2016…severe thunderstorms produced hail up to one inch in diameter near Castle Rock…The Pinery and Watkins.

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In 1995…a cool period with light morning showers and moderate to heavy afternoon showers and thunderstorms pushed rivers already swollen from mountain snow melt over their banks causing minor flooding.  Streams and rivers such as the South Platte and Boulder Creek flooded meadowlands…bike paths…roads near streams…and other low lying areas.  No significant property damage was reported and crop damage was unknown.  Rainfall totaled 1.79 inches at the site of the former Stapleton International Airport and only 1.51 inches at Denver International Airport.

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In 1874…an apparent thunderstorm gust front reached the city at 6:40 pm.  Strong southwest winds sustained to 48 mph for a few minutes produced large columns of dust in the city and on the prairie.  There was no rain in the city.

In 1942…a duststorm swept into the city…but no damage was reported.  West winds were sustained to 23 mph.

In 1953…a heavy hailstorm caused an estimated 100 thousand dollars damage across metro Denver.  Larger than golf ball size hail fell in Westminster and north Denver.  Only 1/8 inch hail was measured at Stapleton Airport.

In 1955…west-northwest winds at 35 mph with gusts as high as 58 mph briefly reduced the visibility to 1/2 mile in blowing dust at Stapleton Airport.

In 1981…lightning damaged power lines west of Lakewood and blew up a transformer at the Denver federal center.  Hail 1 to 1 1/2 inches in diameter was reported in Lakewood and on I-25 south of Denver.

In 2001…hail as large as 3/4 inch in diameter was measured near Commerce City.

In 2003…hail to 3/4 inch in diameter fell near central city.

In 2006…unusually warm weather for late May produced two temperature records.  The high temperature of 93 degrees was a record maximum for the date.  The low temperature of 59 degrees equaled the record high minimum temperature for the date.  Both previous records occurred in 1895.

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In 1884…a thunderstorm apparently produced large hail. The hail stones were noted as unusually large…but the diameter of the stones was not measured.  The hail fell for only 5 minutes.  Precipitation from the storm was only 0.05 inch.

In 1898…heavy thunderstorm rainfall totaled 1.74 inches in downtown Denver.  Hail of unknown size accompanied the storm.

In 1981…a woman in Aurora was struck and killed by lightning.  Another bolt injured a boy on a bicycle at about the same time a short distance away.  About half an inch of rain in 20 minutes caused street flooding in the area.  A tornado touched down for about 2 minutes some 3 miles north of Stapleton International Airport.

In 1982…severe thunderstorms produced golf ball size hail in southeast Denver…Aurora…and Strasburg.  The large hailstones undoubtedly damaged some cars in the area. At Stapleton International Airport…only 1/2 inch diameter hail was measured.

In 1991…golf ball size hail fell in Brighton.  No damage was reported.  Later…hail ranging in size from 3/4 inch to 1 1/2 inches in diameter fell over southwestern sections of metro Denver.  In some areas…hail piled up a few inches in depth.

In 1994…thunderstorm wind gusts to 65 mph damaged 16 small airplanes and a hangar at centennial airport.

In 2001…severe thunderstorms produced large hail across metro Denver.  Hail as large as 1 inch in diameter fell in Lakewood…Wheat Ridge…northwest Denver…near Watkins… Bennett…and Keenesburg.  Hail 3/4 inch or larger fell in Brighton.  Thunderstorm winds gusted to 58 mph at Denver International Airport.  A small tornado (f0) touched down near Bennett…but did no damage.

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In 1934…the low temperature dipped to only 66 degrees…the all-time record highest minimum temperature for the month of May.

In 1958…a microburst caused a brief wind gust to 56 mph at Stapleton Airport.

In 1964…heavy rain caused flooding in the Harvey Gulch area of southeast Denver.  The high water damaged homes… Businesses…streets…and bridges.  At Stapleton International Airport…1.33 inches of rain were measured with 1.76 inches total rainfall on the 29th and 30th.  The heavy rain during the last week of the month was the first significant precipitation since April 3rd.

In 1967…3/4 to 1 inch diameter hail stones fell in the city of Denver…but caused no reported damage.  Hail as large as 3/4 inch was measured at Stapleton International Airport.

In 1975…the heaviest last snowfall of the season occurred when 5.6 inches of snow were measured at Stapleton International Airport.  Rain all day on the 28th changed to snow on the 29th and accumulated to a depth of 4 inches on the ground.  Northwest winds gusted to 31 mph. Precipitation (rain and melted snow) on the 28th and 29th totaled 1.48 inches.

In 1982…one man was killed and two others injured by a lightning strike as they stood under a tree in the city of Denver’s Washington park.

In 1987…7/8 inch diameter hail fell near Castle Rock.

In 1990…thunderstorms over metro Denver produced several small funnel clouds and two small tornadoes.  The first tornado (f0) touched down in northwest Denver and caused roof damage to a house and snapped off the tops of several trees.  A second tornado (f1) touched down in Northglenn and moved into Thornton damaging a group of self storage garages…several vehicles…a wooden fence…several trees… And the roof of an auto parts store.  No injuries were reported.  The storms also caused minor street flooding across northern and western sections of metro Denver. Rainfall totals ranged from 1 to 3 inches.  Lightning started a small fire at a home in northwest Denver.  The fire was confined to the front rooms and was quickly extinguished.  Snow plows were used to clear 2 to 4 inches of pea to marble size hail from a stretch of U.S. Highway 285 in Turkey Creek Canyon.  Lightning felled a tree in northeast Denver…while strong winds snapped off several large tree limbs in the same area.  Thunderstorm rainfall totaled 0.82 inch at Stapleton International Airport where southwest winds gusted to 30 mph.

In 1991…lightning struck a 13 year old boy in a field in Fort Lupton.  The boy was in critical condition in an area hospital for 2 days before recovering.

In 1995…lightning struck a soccer goal post and injured 6 adults viewing a soccer game in Arvada.  Although no one received a direct hit from the lightning…all escaped with only minor injuries…except one woman who was hospitalized.

In 1996…large hail…3/4 to 1 1/2 inches in diameter… Struck Lakewood and west Denver.  Lightning sparked a small fire when it struck an oil storage tank 5 miles west of Brighton.

In 2001…lightning sparked a fire in an apartment complex in Aurora…forcing the evacuation of 24 units.  Most of the fire damage was confined to the attic.  Damage was estimated at 100 thousand dollars.

In 2004…a man and his son were struck by lightning while practicing on the driving range at the meadows golf club in southwest metro Denver.  The father was killed by the bolt…and his 16 year old son seriously injured.  Three other people standing nearby received only minor injuries.

In 2010…hail up to 7/8 inch in diameter was reported in Broomfield.

In 2017…an isolated thunderstorm produced hail up to 7/8 inch in diameter near Centennial.

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In 1894…heavy rain combined with snowmelt runoff caused widespread flooding over the South Platte River basin. Rainfall was heaviest in the foothills where 5 to 8 inches were measured over the 4 days.  Heavy rainfall west of Boulder flooded mining towns and damaged mining properties.  In the canyons above Boulder…railroads and roads were washed out along with many bridges.  The floodwaters spread into central Boulder and covered a wide area from University Hill north to near Mapleton Hill to a maximum depth of 8 feet.  Many houses were swept away…and every bridge in Boulder was destroyed. A few people…trapped in their homes by the floodwaters… Had to be rescued.  However…the gradual rise of the flood waters resulted in only one death.  Boulder creek spread to a width of nearly one mile in the pasture land to the east of Boulder.  Extensive flooding on left hand creek north of Boulder washed away railroad and wagon bridges.  The heavy cloudbursts caused flooding on bear creek…which washed away bridges…railroad tracks…and structures and destroyed the canyon roadway.  Morrison sustained the heaviest flood damage on Bear Creek.  In Denver…rainfall totaled only 1.50 inches on the 30th and 31st…but the heavy rainfall on upstream tributaries of the South Platte River caused the river to rise as much as 10 feet above the low water mark in the city…which caused some flooding of pasture land downstream to a depth of 6 feet near Brighton.