The first half of June is when Colorado’s severe weather season really kicks into high gear and our look back at this week in Denver weather history reflects that. Numerous flooding, hail, and tornadic events punctuate just how dangerous and damaging our weather can be this time of year.

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In 1999…damage from several hailstorms in and near metro Denver totaled 35 million dollars. About 17.5 million dollars was from automobile claims with another 17.5 million in homeowner claims. The areas hardest hit by the storms included Castle Rock…Commerce City…Evergreen… And Golden.

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In 1901…south winds were sustained to 45 mph with an extreme velocity to 47 mph.

In 1917…northwest winds were sustained to 40 mph with gusts to 45 mph.

In 1927…flooding on Little Dry Creek in Englewood resulted in two deaths.

In 1947…a trace of snow fell over downtown Denver during the early morning. This was the latest last snow of the season (trace or more). This also marked the end of the longest snow season…264 days…from the first snow…a trace…on September 22…1946. High temperature of 43 degrees was a record low maximum for the date. Minimum temperature of 33 degrees was a record low for the date.

In 1971…a funnel cloud sighted over Arvada possibly touched down at the base of the foothills. The public reported 3/4 inch to 1 inch diameter hail over the city of Denver.

In 1974…strong thunderstorm winds caused damage to power lines in metro Denver. Northwest winds gusted to 45 mph at Stapleton International Airport.

In 1975…a thunderstorm wind gust to 56 mph was recorded at Stapleton International Airport.

In 1982…three small tornadoes were sighted near Bennett. One of the twisters caused minor crop and road damage along its path. A brief tornado was sighted by national weather service observers at Stapleton International Airport.

In 1983…3/4 inch hail fell in Boulder. Golf ball to 3/4 inch size hail fell in Arvada…denting cars and house roofs. Over a thousand hail damage insurance claims were filed from the area. Golf ball size hail also fell in Northglenn and Bennett…1 to 2 inch hail in Thornton…2 1/2 inch hail in northeast of Denver. A tornado was sighted 10 miles northeast of Stapleton International Airport; it was only on the ground for 1 to 2 minutes.

In 1984…large hail pelted many parts of southern metro Denver. Fifteen aircraft were damaged by golf ball size hail at Centennial airport. Golf ball size hail was reported in south Denver…and 3/4 inch hail was measured in southeast Aurora.

In 1987…a small weak tornado touched down for about 3 minutes near the intersection of I-70 and Colorado Blvd in northeast Denver. No damage was recorded. A microburst wind gust to 53 mph was recorded at Stapleton International Airport.

In 1991…in the city of Denver…lightning struck a tree under which seven people were picnicking. One person was critically injured. The others received only minor injuries.

In 1992…golf ball size hail fell in Evergreen.

In 1994…microburst winds gusting to 53 mph kicked up some blowing dust at Stapleton International Airport.

In 1996…lightning struck a house in Parker…which sparked a fire. The bolt was strong enough to blow nails out of the drywall in one room. About 85 percent of the house was damaged. No dollar estimate of the damage was available. Lightning also struck a power line in Boulder…which left 250 customers without electricity for a short time.

In 1997…a tornado touched down near Parker…damaging some construction equipment. Hail to 2 inches in diameter was measured in Henderson. One inch diameter hail fell in the city of Denver with 3/4 inch hail measured in Lakewood.

In 1999…hail as large as 1 1/2 inches in diameter struck Hudson. A funnel cloud was sighted by ramp personnel to the east of Denver International Airport.

In 2003…lightning blew a hole in the roof of a house in Highlands Ranch. The bolt knocked several holes in the bedroom ceiling and damaged the home’s electrical system.

In 2004…lightning struck a home in Louisville…but caused only minor damage.

In 2006…a strong microburst wind gust…estimated at 69 mph… Ripped the roof off a horse barn near the intersection of Havana Street and Smith Road in Denver. A 13 year old girl was injured…when she was thrown from a horse inside the barn at the time the roof was being torn off. A thunderstorm produced a microburst wind gust to 54 mph and a trace of rainfall at Denver International Airport. A severe thunderstorm produced hail to 0.75 inch near Watkins.

Continue reading June 12 to June 18 – This Week in Denver Weather History →

The first part of June typically brings some of Denver’s most eventful weather of the year and we clearly see that in our look back at this week in Denver weather history. From many damaging hail and wind events to heavy rains that resulted in flooding and even the Southlands Mall tornado of 2009 it has been an eventful week in history.

From the National Weather Service:

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In 1921…heavy rainfall for nearly a week…on top of streams already swollen by mountain snowmelt…produced widespread flooding over the South Platte River basin…including the tributaries through the canyons to the west and southwest of Denver. Heavy rainfall over the 6-day period totaled 3.36 inches in Boulder…4.98 inches in Morrison…4.27 inches in Castle Rock…and 2.94 inches in the city of Denver. Rainfall amounts in the foothills were estimated between 3 and 6 inches. The narrow-gage tracks of the Colorado and southern railroad were destroyed in the Platte Canyon. From the mouth of the canyon through the city to near Brighton… The river spread from 1/2 to nearly 1 1/2 miles wide… Flooding farm and pasture land and destroying or damaging many bridges. In the city…many businesses along with as many as 500 homes were inundated…forcing their evacuation. Bridges were swept away. The high waters flooded the rail yards and stock yards in lower downtown…closing three adjacent packing houses. The heavy rains also caused flooding on Boulder creek in Boulder on the 6th.

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In 1965…lightning and an 18-hour rain storm damaged streets and roads and telephone and power lines across metro Denver. Precipitation totaled 2.77 inches at Stapleton International Airport where the visibility was reduced to 3 miles at times from pre-frontal thunderstorms and heavy upslope rains.

In 1998…a late season snow storm struck the Front Range foothills. Up to 5 inches of snow fell in Coal Creek Canyon. Light snow also fell over western sections of metro Denver and briefly at Denver International Airport. Snow covered the grass at the Denver federal center in Lakewood before melting around mid-morning on the 5th. No snow fell at the site of the former Stapleton International Airport. Several temperature records were set. High temperatures of 47 degrees on the 4th and 49 degrees on the 5th were record low maximums for their respective dates. Minimum temperature of 34 degrees on both the 5th and 6th were record lows for those dates.

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In 1864…high water on the west fork of clear creek caused a small dam near empire to fail…which destroyed several downstream bridges.

In 1885…a windstorm during the afternoon and early evening produced south to southwest winds at sustained speeds up to 42 mph.

In 1937…a trace of snow fell in downtown Denver. This was the latest snowfall of record at the time. Light rain and snow were mixed around mid-day. Precipitation totaled only 0.01 inch. North winds were sustained to 20 mph.

In 1941…hail of unknown size fell on the city.

In 1961…lightning struck and injured an airman outside a base classroom at Lowry Air Force Base. Funnel clouds were sighted near Frederick and firestone north of Denver. The one near Frederick briefly touched down in an open field but caused no damage. Heavy rain and hail hit the Fort Lupton area causing damage to crops. Heavy rain in Frederick added to the flood damage of the 3rd. A pilot reported a funnel cloud that touched down briefly and then dissipated south of Castle Rock.

In 1965…a lightning-caused fire destroyed a mountain home near Rollinsville.

In 1988…a tornado touched down 5 miles east of Lafayette near I-25 and stayed on the ground for 15 minutes. The twister hit a campground…demolishing one trailer and damaging six others…along with 4 cars. The rope-like funnel also blew down fences…signs…and electrical boxes. The twister moved a 1500-pound hay wagon 150 feet. Total damage to the campground was estimated at 50 thousand dollars. Another tornado touched down between Broomfield and Lafayette…staying on the ground for about 20 minutes. The twister hit a subdivision…unroofing one abandoned house and causing minor damage to a dozen others. A four- car garage and three barns were destroyed. At one location a chain link fence…a satellite dish…and a shed were destroyed…while the deck and garage of the house were damaged. A grain storage tank was moved 200 feet. There were reports of boards being blown through walls; one came through a kitchen.

In 1992…lightning struck a 15-year-old boy…causing minor injuries…in Adams County 6 miles north-northeast of Stapleton International Airport. Thunderstorm winds gusted to 63 mph at Jefferson County Airport near Broomfield…to 58 mph at the U.S. Atomic Energy Commission’s facility at Rocky Flats…to 58 mph in Thornton…and to 48 mph at Stapleton International Airport where 1/8 inch diameter hail fell.

In 1996…strong microburst winds up to 60 mph damaged several trees in Boulder…snapping large branches 1 to 2 inches in diameter.

In 1997…a woman was struck by lightning as she was walking to her car in Nederland. The lightning bolt apparently struck a nearby power line and arced into her left hand. She received minor injuries.

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In 1977…lightning caused several power outages and moderate damage to a railroad building.

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In 1954…thunderstorm winds at speeds of 50 mph with gusts as high as 59 mph briefly reduced the visibility to 1 mile in blowing dust at Stapleton Airport.

In 1967…the public reported golf ball to 1 3/4 inch diameter hail in the city…3 miles west-southwest of Stapleton International Airport. The amount of damage was unknown. Thunderstorm winds gusted to 46 mph at Stapleton International Airport.

In 1981…hail to 3/4 inch in diameter was reported in east Denver.

In 1990…golf ball size hail was reported near Strasburg on I-70 east of Denver.

In 1991…a tornado was spotted by national weather service personnel and weather spotters…14 to 17 miles northeast of Stapleton International Airport. A funnel cloud was sighted over south Aurora just east of Buckley Field…and a tornado was spotted just east of Watkins. No damage was reported. Thunderstorms moved through Aurora and dropped hail up to 1 inch in diameter. The storms also produced heavy rain… Up to 1 inch in 30 minutes…causing flooding of streets. Water was reported hood deep…stranding motorists. Water covered fire hydrants at some intersections.

In 1995…a waterspout sighted over Standley Lake in northern Jefferson County…quickly dissipated once it reached shore. A brief tornado…which was momentarily visible by a dust debris cloud on the ground…damaged the roof of a house in Westminster. A funnel cloud was sighted just south of Lafayette. Hail from 3/4 to 1 1/4 inches in diameter fell over north Boulder. Thunderstorm outflow produced north wind gusts to 44 mph at Denver International Airport.

In 1997…a tornado touched down near baseline reservoir just east of Boulder. The tornado struck a home…tearing off part of the roof. A storage building nearby was nearly leveled and 5 trees were uprooted. The twister then moved onto baseline reservoir…forming a huge waterspout. Several recreational vehicles and a boat dock were also damaged. A nearly stationary line of thunderstorms dumped 4.60 inches of rain on portions of Thornton. Extensive flooding of streets and underpasses and other low lying areas was reported. Several businesses were flooded and basements in the area were damaged. Rainfall totaled 1.02 inches at Denver International Airport and 1.24 inches at the site of the former Stapleton International Airport. Large hail…up to 1 3/4 inches in diameter…fell over the city of Denver with 3/4 inch hail measured in Littleton and near Henderson.

In 1999…high winds developed for a brief time in and near the foothills of Boulder. The Gamow Tower on the University of Colorado campus recorded a wind gust to 87 mph. Winds peaked to 71 mph atop Niwot Ridge near the continental divide west of Boulder.

In 2003…a small tornado touched down near Strasburg…but did no damage.

Continue reading June 5 to June 11 – This Week in Denver Weather History →

There are many notable events on our look back at the weather history books for this week but one in particular stands out. It was 30 years ago this week, on June 3, that the infamous Thornton tornado struck. This twister still stands as the most damaging tornado to have ever struck the Denver metro area.

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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 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.

Continue reading May 29 to June 4 – This Week in Denver Weather History →