Late spring and early summer weather hazards abound in Colorado. Looking back at this week in Denver weather history we see many examples including wildfires, deadly lightning, damaging lightning and dangerous flooding.
From the National Weather Service:
12-17
In 2000…two large wildfires developed in the Front Range foothills as careless campers and very dry conditions proved to be a dangerous combination. Strong winds gusting in excess of 60 mph on the 13th fanned the flames… Spreading both wildfires out of control. Winds gusted to 78 mph atop Niwot Ridge near the Continental Divide west of Boulder. The Hi Meadows wildfire…about 35 miles southwest of Denver…consumed nearly 11 thousand acres and 80 structures…mostly high priced homes. The Bobcat wildfire…located about 12 miles southwest of Fort Collins… consumed nearly 11 thousand acres and 22 structures. Late on the 16th…a strong cold front moved south over the great plains into northeastern Colorado. Low level upslope conditions developed in the wake of the front…producing 2 to 4 inches of snowfall overnight at elevations above 8 thousand feet. Firefighters were able to contain both fires shortly thereafter.
15-16
In 1963…heavy rain and hail ravaged metro Denver. In southeast Denver…heavy rain flooded homes and streets. Hail to a depth of 4 inches on the ground stripped trees and plants and drifted to depths of 3 to 4 feet in some areas. Flood waters on the valley highway were 19 feet deep in places…trapping many cars. Many creeks were running over their banks. On the 15th…the main thunderstorm cell passed over south Denver…dumping as much as 4 inches of rain in 90 minutes. Precipitation at Stapleton Airport totaled 0.91 inch on the 15th and 1.31 inches on the 16th. A funnel cloud was sighted briefly 4 miles to the south-southeast of Stapleton Airport on the 15th. Damage from hail and flooding amounted to near a million dollars.
15-17
In 2021…the temperature in Denver reached 100 degrees for three consecutive days: 101…100…100 respectively. Each established a new record high for the day. It was also the earliest occurrence of such a streak. A record high minimum of 68 also occurred on the 17th.
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In 1950…very heavy rain and hail storms in southwest Denver caused an estimated 750 thousand dollars in hail and flood damage. Thunderstorms produced 2.06 inches of rain at Stapleton Airport with 2.23 inches of rain measured in downtown Denver.
In 1965…a tornado…15 miles south-southeast of Denver… Touched down and damaged two houses in northern Douglas County. Three golfers at a country club and a women who lived north of Castle Rock were injured by falling structures.
In 1983…a microburst wind gust to 54 mph was recorded at Stapleton International Airport.
In 1984…a tornado touched down briefly in Parker. No damage was reported.
In 1986…lightning injured 5 people just north of the Denver city limits in Adams County. The victims were members of a drum and bugle corps and were standing near a metal scaffold. Heavy rain from the storm also caused street flooding in the metro area.
In 1991…hail to golf ball size fell at Conifer.
In 1992…a rare mid-June high wind event wreaked havoc over metro Denver when a pacific cold front moved across the Rocky Mountains. Strong winds at speeds of 40 to 50 mph were common along the Front Range foothills. Winds reaching 107 mph in the foothills west of Denver and 79 mph at Longmont…caused damage ranging from trees being toppled to large trucks being rolled over. Strong winds estimated at 75 mph rolled a 35-foot truck carrying building supplies on U.S. Highway 36 north of Boulder. The truck driver and a passenger as well as the driver of another car were slightly injured. The winds downed power lines. The gambling towns of central city and Blackhawk were without power for a couple of hours. West winds reached 43 mph at Stapleton International Airport.
In 1996…a small tornado touched down in the foothills southwest of Boulder near Pinecliffe…knocking down 50 to 100 large pine trees. A house nearby sustained damage when shingles were ripped from the roof. The tornado also picked up a 17-foot sailboat with attached trailer and carried it 25 feet into a nearby tree. In addition… Thunderstorm wind gusts to 46 mph were measured at Denver International Airport.
In 2004…hail as large as 1 inch in diameter fell near Castle Rock. Hail to 3/4 inch was measured near Bennett.
In 2005…severe thunderstorms produced hail as large as 1 inch in diameter in Centennial.
In 2011…severe thunderstorms produced and damaging across parts of metropolitan Denver. In Lakewood…a tree blew down and landed on at least five cars. At Centennial Airport…a section of a roof on a hangar was ripped off the strong winds. A peak wind gust of 46 mph was recorded at Centennial Airport and Denver International Airport in the evening.
In 2022…severe thunderstorms produced large hail across parts of Boulder and Weld counties. The hail ranged from 1 to 1 1/2 inches at Allenspark…Ft. Lupton…Hudson and Lochbuie.
16-17
In 1965…on the afternoon and evening of the 16th…violent thunderstorms produced extremely heavy cloudbursts of rain over the palmer divide and sent a wall of water as high as 20 feet down both branches of Plum Creek into the South Platte River and through metro Denver. The heavy rainfall produced the most devastating flood in the history of Denver. Rainfall totaled 14.0 inches in 3 hours at both Larkspur and Palmer Lake with 12.0 inches recorded in Castle Rock. The flood waters caused extensive damage to roads and bridges in larkspur…Castle Rock…and Sedalia…including washing out the I-25 bridge over East Plum Creek in Castle Rock. The citizens of metro Denver received reports of the flooding to the south and had a few hours to initiate evacuation procedures along the South Platte River…greatly limiting the loss of life. By evening…the flood reached Littleton where a heroic effort was made to save nearly 150 horses at the Centennial Racetrack…which was completely inundated by the flood waters. As the flood proceeded through the city of Denver…the river became more than 1/2 mile wide and destroyed all homes…trailer courts… And businesses in its path. The waters contained debris ranging from refrigerators to old cars. As many as 26 bridges were damaged or destroyed…including the 6th Avenue freeway bridge across the South Platte. Both Public Service Company power plants were shut down by the flood. The King Soopers grocery chain bakery was inundated. About midnight… The torrent crested at 25 feet above normal with flow exceeding 40 times normal and is the record flood on the South Platte and many of its tributaries. The flood caused 230 million dollars in damage and 8 deaths along the entire South Platte River basin. The intense rain also caused flooding along Cherry Creek in Denver…on Toll Gate and Sand Creeks in east metro Denver…and on Kiowa and Bijou creeks to the east of Denver. The South Platte River flood closed nearly every major east-west highway into Denver…nearly isolating the city. The flood caused heavy damage to state and county roads in the area. Railroads were also hard hit with the main yards in lower downtown inundated. Sewerage… Water supply facilities…and irrigation works also received heavy flood damage. The flood crest did not reach Nebraska until the 20th.
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In 1915…northwest winds were sustained to 41 mph with an extreme velocity to 42 mph.
In 1967…this was the 24th consecutive day with a trace or more of precipitation from May 25th. Precipitation totaled 5.87 inches during the period…more than a third of the average yearly total.
In 1975…hail more than 2 inches in diameter fell in eastern Aurora.
In 1977…golf ball size hail was reported 3 miles east of Arapahoe County airport…now Centennial Airport. Heavy hail to 3/4 inch in diameter was reported in Littleton… Castle Rock…and Sedalia.
In 1979…a man and a girl were struck and killed by lightning while walking in a park in northwest Denver.
In 1987…3/4 inch hail fell near Boulder.
In 1991…a microburst wind gust to 59 mph kicked up some blowing dust at Stapleton International Airport.
In 1998…hail as large as 3/4 inch in diameter fell in Boulder.
In 2003…lightning struck a feeder line…knocking out the electricity to about 3000 residents in Littleton. A lightning strike caused minor damage to the roof and attic of a home in Lafayette. Another lightning strike caused minor roof damage to a residence in Louisville. Yet another lightning strike hit a home in Denver and caused a small attic fire. Hail as large as 1 inch in diameter was measured near Centennial Airport and near Greenland.
In 2009…hail up to 1 inch in diameter was measured near Longmont.
In 2015…a severe thunderstorm produced hail up to 1 1/2 inches in diameter near Arapahoe Park…and up to 1 inch in diameter near Parker.
17-18
In 1964…high winds at speeds of 50 to 60 mph with gusts as high as 75 mph caused damage to homes…power lines…and trees in Boulder. Non-convective west winds gusting to 46 mph caused some blowing dust at Stapleton International Airport on the 17th.
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In 1875…a windstorm produced sustained winds to 45 mph during the morning hours. Numerous forest fires along the base of the mountains were visible from the city.
In 1886…northwest winds sustained to 40 mph were the strongest of the month that year.
In 1987…severe thunderstorms produced lightning…large hail… A tornado…heavy rain…and strong winds across metro Denver. Rainfall totaled 2.50 inches in an hour in Wheat Ridge… Causing minor flooding. I-25 was flooded in north-central Denver…snarling traffic. Hail 7/8 inch in diameter fell in Louisville with 1 1/2 inch hail near Golden and 1 to 1 3/4 inch hail in and near Castle Rock. A tornado touched down briefly in Castle Rock. No damage was reported. Lightning started a small fire that burned half a cabin near Evergreen.
In 1994…a funnel cloud was sighted over Aurora; hail to 1 3/4 inch diameter fell near Brighton; and hail over an inch in diameter fell over Aurora…southeast Denver… Louisville…and Boulder. Lightning struck a home in Henderson 9 miles north of Denver and knocked a hole in the roof…which caused the ceiling to collapse. Hail to 1 1/4 inch diameter was measured at Stapleton International Airport.
In 2002…the Hayman wildfire in the foothills to the southwest of Denver intensified…and the winds aloft carried the smoke plume directly over metro Denver…again creating a dense haze of smoke which blocked the sun. Surface visibilities were again reduced to as low as 1 1/4 miles at Denver International Airport.
In 2004…severe thunderstorms produced hail to 3/4 inch in diameter near Morrison…in Littleton…near Conifer…near Castle Rock…and in Aurora near Cherry Creek.
In 2013…a landspout tornado touched down at DIA. The tornado sent 10 thousand travelers on the concourse…on planes and in the terminal scrambling to get into tornado shelters. The tornado formed just to the south of Runway 35R and then moved slowly northwest between Runway 35R and 35L…and moved to within one third of a mile of Concourses A and B before dissipating. The tornado moved extremely close if not over the ASOS (Automated Surface Observation System) and another low level wind shear sensor at DIA. The ASOS weather observing system reported a 97 mph wind gust…while the wind shear sensor reported a wind gust to 109 mph at the same time indicative of an EF1 tornado. There was only minor damage noted to the equipment. Nine flights were diverted elsewhere during a tornado warning. Severe thunderstorms also produced large hail up to quarter size in Adams and Weld Counties.
In 2014…a severe thunderstorm produced large hail up to quarter size near Buckley Air Force Base. At Denver International Airport…a peak wind gust to 55 mph was observed from the southwest…along with 0.37 inches of water.
In 2015…a severe thunderstorm produced hail…from quarter to half dollar size…near Lafayette…Louisville and Superior.
Continue reading June 16 to June 22: This Week in Denver Weather History
