
The end of July and beginning of August has historically been a rather active one. Looking back at the history books, deadly and damaging lightning, heavy monsoon rains and extreme heat are the dominate extremes we have seen.
From the National Weather Service:
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In 2008…a streak of 24 consecutive days of 90 degrees shattered the previous record of 18 consecutive days established in 1901 and 1874. Ironically…no new single day record high temperatures were set in the month of July. In August however…a record of 104 degrees was set on the 1st…and another record of 103 degrees was set on the 2nd. In addition…a record low min of 70 degrees was set on August 2nd.
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In 1987…a streak of 16 consecutive days of 90 degrees ranked 4th on the list of hot streaks. The record of 24 consecutive days was established in the summer of 2008.
26-27 in 1885…heavy cloudbursts on the palmer divide south of Denver caused flooding on Cherry Creek in the city overnight. The high water washed away street and railroad bridges and a few houses. The flood waters completely inundated the rail yards in lower downtown. This was the worst flood on Cherry Creek since May 19-20…1864…but the damage was mitigated by stream improvements and fewer structures near the channel. There was also no simultaneous flood on the South Platte River to slow the flow of water through the city. Rainfall in the city was only 0.08 inch on the 26th.
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In 1897…an apparent dry microburst produced sustained west winds to 48 mph with gusts to 60 mph and a trace of rain.
In 1901…a thunderstorm produced north winds to 38 mph with gusts to 41 mph and rainfall of only 0.01 inch in downtown Denver. This was the only measurable rainfall of the month… Making this the driest July on record.
In 1953…an unconfirmed tornado in south Lakewood touched down briefly and abruptly dissipated. No damage was reported from the twister.
In 1955…the public sighted a funnel cloud estimated at 500 feet above the ground near the western edge of Lowry Field. Wind estimates up to 60 mph were reported in the vicinity.
In 1956…a severe thunderstorm produced 3/4 inch diameter hail and wind gusts to 48 mph at Stapleton Airport where rain fall totaled 1.08 inches.
In 1965…a tornado was sighted 21 miles south of Denver in Douglas County. No damage was reported.
In 1977…a thunderstorm wind gust to 51 mph was recorded at Stapleton International Airport. A funnel cloud was sighted by an aircraft east of Parker.
In 1982…heavy rain doused Boulder with 1 1/2 to 3 inches of rain over a short period of time…causing extensive street flooding.
In 1984…strong thunderstorms drenched several areas. Rainfall of 1.04 inches occurred in just 20 minutes at Boulder. Downpours also hit Aurora and northeast Denver… Delaying flights at Stapleton International Airport for an hour. Up to 3/4 inch of rain fell in central Aurora in 15 minutes.
In 1989…lightning hit a home in Littleton…setting a bed on fire. Damage was confined to the bedroom.
In 1994…lightning struck a furniture store in Boulder… Igniting a fire which caused major damage to the building and contents.
In 1997…lightning sparked a fire…causing extensive damage to a home in Watkins. Heavy rain caused Lena Gulch to surge 2 feet over its banks in Golden. The fire department had to rescue a man when his van stalled in high waters. High waters from swollen creeks and streams washed out bridges and several sections of road in southeast Aurora. A 200-to-300 foot section of road was washed away where Picadilly Street dips across Coal Creek. Three youths had to be rescued when they became stranded by rapidly rising water in another normally dry creek bed.
In 1999…lightning was suspected of igniting a fire which caused substantial damage to a farm in Hudson. The blaze destroyed a 10-foot by 60-foot metal pole barn…a pick-up truck…a SUV…a boat and trailer…3 four wheeler vehicles… And other farm equipment.
In 2007…a man was struck and killed by lightning while jogging at Matthews Winters Park in Morrison.
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In 1956…96 percent of the total precipitation for the month of July occurred over the last five days of the month. Heavy thunderstorms produced 4.00 inches of rainfall at Stapleton Airport. This amount of precipitation in 5 days or less had been exceeded only 3 times in previous record. The last time had been in December of 1913 as snow. Considerable property damage occurred across metro Denver from flooding.
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In 1882…intense thunderstorm lightning struck a number of places in the city…but no significant damage was reported.
In 1910…heavy thunderstorm rainfall totaled 2.21 inches in downtown Denver. Rainfall was 1.11 inches in an hour during the early afternoon.
In 1922…heavy rainfall to the south of Denver caused Cherry Creek to rise to the top of the retaining walls in the city. The creek did not flood; however…the large volume of water discharged into the South Platte River did inundate a few blocks of Globeville. Flooding also occurred along bayou creek near Franktown to the south of the city.
In 1923…thunderstorm winds were sustained to 38 mph with gusts to 52 mph.
In 1957…iridescent cirrocumulus clouds of unusual formation and brilliant color…oriented from southwest to northeast over metro Denver…were sighted by U.S. Weather Bureau observers at Stapleton Airport shortly after noon.
In 1966…heavy rains from a severe thunderstorm caused flash flooding on Deer Creek…southwest of Littleton. A child was injured when washed from a car caught in the flood waters. The flooding damaged property along the creek. Strong winds damaged several houses in suburban Littleton.
In 1970…a microburst wind gust to 52 mph was recorded at Stapleton International Airport.
In 1974…a tornado was sighted just east of Buckley Field in Aurora. No damage was reported.
In 1982…up to 2.50 inches of rain drenched an area just southwest of Denver in 30 minutes. This was the second day of heavy rain across portions of metro Denver.
In 1984…1.25 inches of rain fell in 45 minutes in Arvada. Minor flooding occurred on Bear Creek after a small dam broke.
In 1989…lightning killed two men in Arvada. They were taking wash from a clothesline when a bolt hit the older man…39… Killing him instantly. The bolt then traveled along the line…which was stretched between 2 tall trees…and hit his 26-year-old brother who died the next day.
In 1996…several weak tornadoes developed along a thunderstorm outflow boundary that moved into southern weld…northern Jefferson…and Adams counties. The tornadoes sighted near Bennett…Barr Lake…and in Arvada caused little damage. Strong thunderstorm winds downed several trees in the city of Denver and toppled several trees 7 miles west of Arvada where shingles were blown off several houses. Thunderstorm wind gusts reached 58 mph in Broomfield.
In 1997…a weak tornado touched down briefly in Parker… Damaging a greenhouse. Twenty pieces of the fiberglass roof were ripped away. Heavy rainfall in the foothills washed out some culverts in the pine and Conifer areas. Heavy rainfall spread over the plains with 4 to 7 inches reportedly falling near Hudson. Several County roads were washed out between Fort Lupton and Hudson. Several basements in the area were flooded up to the ceiling. Standing water…up to 3 feet deep…was reported in some backyards. Later in the evening…a flash flood killed 5 people and injured 40 others in two mobile home parks in Fort Collins. The torrential rainfall also caused extensive damage on the Colorado state university campus. Thunderstorm rainfall totaled 0.80 inch at Denver International Airport and 1.09 inches at the site of the former Stapleton International Airport.
In 1999…heavy rainfall…up to 3 inches an hour…triggered a massive rock and mudslide along I-70 near Bakerville. The slide area was about 200 feet wide and 20 feet deep. Several other smaller slides were also reported along the highway. As a result…I-70 was closed for nearly 25 hours in both directions until the debris could be cleared from the roadway. The blockage of I-70 was one of the longest in the history of the highway in Colorado. A severe thunderstorm produced a wind gust to 64 mph at Denver International Airport. The storm also produced 1.56 inches of rain and briefly reduced the visibility to 1/4 mile.
In 2004…a severe thunderstorm produced hail as large as 1 inch in diameter in Thornton.
In 2010…a wet microburst produced very heavy rain and torrential hail in Boulder County…in the vicinities of Caribou…Nederland and Eldora. Flash flooding washed out sections of County roads 126 and 128 near Caribou. Several large boulders had fallen across the roadways. Considerable flooding was reported in Nederland. Water was also observed running across County Road 130…between Eldora and Nederland. The hail had accumulated up to 8 inches deep near Eldora. Several vehicles were stuck in the ice…forcing the temporary closure of cr130 and the Lake Eldora ski road until snowplows could clear away the hail. Lightning strikes caused minor damage to two local businesses in Nederland. At Denver International Airport…a thunderstorm produced 0.30 inches of rain along with a peak wind gust to 38 mph.
In 2012…a tornado touched down briefly at the southeast corner of Mt. Evans near Lincoln Lake. The estimated elevation where this tornado touched down was near 12500 feet. This would make this tornado one of the highest ever observed in the U.S.
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In 1889…dense smoke from forest fires in the mountains obscured the sun over the city for three days.
In 1971…a vigorous cold front late on the 28th produced northeast wind gusts to 39 mph and record breaking cold temperatures on the 29th and 30th. The temperature dipped to 47 degrees on the 29th and 43 degrees on the 30th… Setting record minimums for the dates. Upslope cloudiness along with rain and fog early on the 29th helped set a record low maximum temperature of 58 degrees for the date.
Continue reading July 27 to August 2: This Week in Denver Weather History