The effects of our annual monsoon season are portrayed in detail in our look back at this week in Denver weather history. Numerous cases of flooding resulting from heavy rainfall are seen as are other severe weather events including hail and even tornadoes.

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.
27-31 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 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.

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In 1878…a total eclipse of the sun was observed at 2:20 pm. From before to during the eclipse…the temperature in the sun fell from 114 degrees to 82 degrees…while the shade temperature fell from 89 degrees to 83 degrees.

In 1880…heavy thunderstorm rain and hail flooded streets and ditches.

In 25 minutes…0.76 inch of rain fell on the city along with large hail to 3/4 inch in diameter. There were no strong winds with the storm.

In 1890…a thunderstorm produced sustained west winds to 48 mph with gusts to 60 mph…but only 0.01 inch of rain.

In 1956…heavy rain and hail fell over west and north Denver.

In 1964…hail to 3/4 inch in diameter fell at Lowry Airfield.

In 1978…a small tornado was sighted just east of Parker. No damage was reported.

In 1989…heavy rain drenched all areas of the Front Range… Both in the foothills and adjacent plains. Amounts of 1 to 3 inches were general over the area. Damage was confined to a few minor road washouts and some street…basement…and crop flooding. Thunderstorm rainfall totaled 1.44 inches at Stapleton International Airport where north winds gusted to 43 mph. Lightning struck a 250 thousand dollar home near Nederland and started a fire which destroyed all of it except two garages. Lightning started a fire in a home in Evergreen. It reached the house by hitting a tree…then traveling through a metal clothesline strung between the tree and the building.

In 1995…thunderstorm winds gusted to 59 mph in Brighton. Thunderstorm winds from the south-southeast gusted to 41 mph at Denver International Airport. High temperature of 99 degrees was a new record maximum for the date in Denver.

In 1997…heavy rain caused flooding in an apartment building in Westminster. Several residents had to be evacuated from their apartments. A woman in aspen park received minor injuries…when lightning passed through an office window and struck her. She suffered temporary blindness for about 15 minutes.

In 2003…hail as large as 1 inch in diameter pelted Conifer… Highlands Ranch…and Franktown.

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In 1997…heavy rain caused flooding and flash flooding in central portions of Adams and Arapahoe counties. Two homes were extensively damaged when water flooded the basements and adjacent pasture area in Strasburg. Water 4 to 5 feet deep had pooled in the lower lying areas of the town. A portion of Quincy Road was closed in Arapahoe County when 4 feet of water covered the roadway. Rainfall totaled 3.06 inches at Denver International Airport…establishing a new record for 24-hour rainfall in July. The previous record was 2.42 inches set in 1965 on the 24th and 25th.

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In 1879…lightning struck a brick kiln in north Denver. Three men were knocked senseless…but all recovered. Rainfall in the city was only 0.09 inch.

In 1881…a thunderstorm dumped heavy rain and hail on the city…causing street flooding and much damage. A heavy torrent of rain fell with 1.10 inches measured in just 20 minutes. Storm total rainfall was 1.60 inches. The rain turned streets into running streams. Wood street crossings were torn up and washed away. The storm caused great damage by flooding many cellars where goods were stored. The brick yards suffered severe damage when the heavy rainfall destroyed many unfired bricks.

In 1913…northeast winds were sustained to 41 mph with gusts to 48 mph.

In 1939…a thunderstorm produced 0.08 inch of rainfall. This was the only measurable precipitation of the month…making the month the second driest July on record.

In 1961…heavy rain and lightning disrupted power lines and caused flooding in Denver. Thunderstorm rains totaled 1.60 inches at 11th and Lincoln in central Denver.

In 1972…the temperature climbed to a high of 100 degrees at Stapleton International Airport.

In 1983…hail 3/4 to 1 inch in diameter fell in central and southeast Denver and in Littleton. Rainfall of 1.50 inches occurred in just 30 minutes in Littleton. There was some street flooding in both cities with wind gusts up to 55 mph.

In 1984…central Aurora was hit by a downpour that produced 1.80 inches of rain and sent water 2 to 3 feet deep into some streets. Before the rain stopped later in the evening… The storm had dropped as much as 2.80 inches of moisture on the city. Thunderstorm rainfall totaled only 0.82 inch at Stapleton International Airport.

In 1985…a tornado was spotted in open country 10 miles southwest of Bennett. No damage was reported. One inch hail was reported in south Lakewood.

In 1997…one man was killed and his girlfriend critically injured when they were struck by lightning on the Kennedy Golf Course in southeast Denver. Both were struck in the head when they took refuge under a tree during a downpour. Lightning struck a home in unincorporated Arapahoe County east of Buckley Field. The fire started in the electrical panel boxes…causing extensive damage to the home. Heavy rain and hail triggered a flash flood in Boulder…which sent water through a window of the financial aid office on the University of Colorado campus. In addition…ceiling tiles…carpets…and dressing rooms were damaged at the Coors Events Center when a pipe draining rainwater broke during the downpour. In all…10 buildings on the campus received water damage estimated at 100 thousand dollars. Hail as large as 1.25 inches in diameter accompanied the heavy rain in Boulder. Thunderstorm rainfall totaled 2.71 inches at Denver International Airport where west winds gusted to 41 mph. This was the greatest calendar day official precipitation ever recorded in July.

In 1998…heavy rain…up to 3 inches in an hour…caused flash flooding problems from Castle Rock to Parker. I-25 north of Castle Rock was closed as high waters covered sections of the highway. Some cars were left floating in the flood waters.

In 2001…a severe thunderstorm produced a wind gust to 70 mph at a wind sensor on the northeast corner of Denver International Airport.

In 2004…a severe thunderstorm produced wind gusts to 71 mph in Evergreen.

In 2005…the temperature climbed to a high of 101 degrees at Denver International Airport. This was a new record maximum temperature for the date.

In addition…this was the 7th day of the month with a high temperature of 100 degrees or more…which set a new Denver record for the most 100 degree days in a month…for a season…and in a year.

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In 1873…the all-time lowest recorded temperature in July… 42 degrees…occurred. The same temperature also occurred on July 4…1903.

In 1874…during the late afternoon rain and hail fell for 5 minutes followed by brief heavy rain. Pieces of solid ice of irregular shape fell upon the roof of the station. The hail stones measured 1 1/2 inches in diameter. Precipitation (rain and melted hail) was only 0.16 inch.

In 1889…the high temperature climbed to 100 degrees in downtown Denver.

In 1919…heavy thunderstorm rainfall totaled 2.59 inches in downtown Denver during the evening. Rainfall was 1.90 inches in an hour…a new record at that time.

In 1961…over an inch of rain in a short period of time caused flooding of streets and basements in Denver. Rainfall totaled 1.30 inches at 11th and Lincoln in central Denver.

In 1964…the temperature reached 91 degrees in Denver…making this the 27th day of the month that the temperature reached 90 degrees or more. This is the all time record for 90 degree days in a month in Denver.

In 1972…one inch diameter hail fell in Hudson northeast of Denver.

In 1976…during the evening hours extremely heavy thunderstorm rains produced flash flooding in Big Thompson Canyon which killed 144 people between Estes Park and Loveland. No significant weather occurred in metro Denver at the time.

In 1987…1 inch diameter hail fell in Lakewood and 3/4 inch hail fell near Louisville. Southeast Boulder County was drenched with 1.25 inches of rain in just 20 minutes.

In 1993…thunderstorm winds damaged a chimney of a home near Parker.

In 1996…a weak tornado (f0) was sighted 12 miles east of Denver International Airport. No damage was reported.

In 1998…heavy monsoonal thunderstorm rain triggered a mud slide in Blackhawk. The mudslide blocked Main St. and caused an estimated half million dollars in damage to a casino. Heavy thunderstorm rain…up to 3 inches in an hour…caused a flash flood along Buffalo Creek. Portions of County road 126 just south of the town of Buffalo Creek were washed out. The flood waters nearly washed away the bridge as mud and debris slammed into the structure. Hail to 1 3/4 inches in diameter fell near Idaho Springs.

In 2004…severe thunderstorm winds toppled a 65-foot blue spruce tree in Parker. The tree landed on a home damaging the roof and gutters. The downed tree poked dozens of holes into the shingles.

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In 1888…heavy rain in the mountains and foothills caused flooding on clear creek in Golden. The high waters also washed away portions of the railroad tracks in the canyon between Idaho Springs and Golden.

In 1901…the temperature reached a high of 100 degrees in the city.

In 1902…the high temperature climbed to 100 degrees in downtown Denver.

In 1914…a thunderstorm produced 1.00 inch of rainfall in just 21 minutes and north winds sustained at 43 mph with gusts to 50 mph. Rainfall totaled 1.17 inches.

In 1938…the temperature climbed to a high of 100 degrees in downtown Denver…which is the record maximum for the date. The temperature was also recorded on this date in previous years.

In 1976…flight operations at Stapleton International Airport were suspended for 90 minutes when the airport tower radar was knocked out and water reached a foot deep on some taxi ramps after 1.50 inches of rain fell in one hour. Heavy rain also caused minor flooding in east Denver and Aurora where lightning damaged the roof of a home and injured the owner. One young man was swept down a flooded ditch…but was rescued by firemen. A number of rafts were floated in flooded streets. Thunderstorm rainfall totaled 1.71 inches at Stapleton International Airport.

In 1978…a tornado damaged a house and broke a power pole 5 miles northwest of Parker. A microburst wind gust to 52 mph briefly reduced visibility to 1 mile in blowing dust at Stapleton International Airport.

In 1985…heavy thunderstorms roared through the southern and western sections of metro Denver…producing large hail and heavy rain. Lightning hit a recreational vehicle trailer causing it to burn. There was a lot of street flooding over western suburbs where rainfall totaled over 2 inches in some areas. One inch diameter hail was reported in Littleton and near Evergreen. Hail piled 4 to 6 inches deep at Tinytown in the foothills southwest of Denver.

In 1990…a small rope-like tornado was spotted in open country 15 miles southeast of centennial airport. No damage was reported from the twister.

In 1992…pilots reported a funnel cloud near the construction site of the new Denver International Airport. A few minutes later…a tornado was reported near Bennett. The tornado remained on the ground for about 18 minutes and was visible from the National Weather Service office at Stapleton International Airport. Thunderstorm wind gusts to 70 mph were reported near Bennett and Watkins with a wind gust to 60 mph at Brighton. Two men were injured when struck by lightning. A young man sustained serious injuries when struck by lightning while jet skiing on Cheery Creek Reservoir. A man received only minor injuries when struck by lightning while golfing in Westminster.

In 1994…heavy thunderstorm rains in the foothills west of Denver caused the closure of the Virginia Canyon Road north of Idaho Springs by rocks and debris.

In 2001…a 34 year old man on the South Platte River bike path in Denver received minor injuries when lightning struck a nearby tree. Lightning…coupled with strong thunderstorm winds…knocked out electrical power to about 10 thousand homes and businesses in Golden.

In 2006…strong thunderstorms hit southern metro Denver. A severe thunderstorm wind gust estimated to 71 mph knocked down a tree in Aurora near Cherry Creek. Lightning sparked a fire in a home near lone tree and struck a transformer at an RTD light rail station at Interstate 25 and Yosemite Street. Heavy thunderstorm rainfall forced the closure of Arapahoe Road between Holly and Quebec streets due to high water. Flooding was also reported near Park Meadows Mall and Greenwood Village. Heavy rainfall also caused flooding in Highlands Ranch…lone tree…and Parker. Water up to 6 inches deep was reportedly running over the roads.

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In 1878…the high temperature reached 100 degrees in downtown Denver.

In 1911…an apparent dry microburst produced sustained west winds to 42 mph.

In 1972…one workman was killed and another injured when a strong gust of wind destroyed a partially completed apartment building in south Denver. Hail to 1 3/4 inch diameter fell in Golden.

In 1973…hail to 3/4 inch diameter was reported in Boulder.

In 1986…a major outbreak of severe thunderstorms occurred along the Front Range. Thunderstorms developed explosively. Some places were hit by large hail twice. Two inch diameter hail broke car windows on I-25 west of Brighton…and up to 1 1/4 inch hail broke windows in Thornton. Baseball size hail damaged several planes near Watkins. Funnel clouds were sighted around Aurora. Hail over 1/2 inch in diameter covered the ground 3 to 4 inches deep at Hudson northeast of Denver. Most of the hail fell north of metro Denver…but 3/4 inch diameter hail was measured at Stapleton International Airport. Total damage from the hail storms this day was estimated at over 10 million dollars.

In 1991…late afternoon thunderstorms produced heavy rain across metro Denver. Two feet of water covered parts of I-25 in southeast Denver…while one foot of water covered parts of U.S. Highway 285 in Englewood. Thunderstorm rainfall totaled 0.50 inch at Stapleton International Airport.

In 2001…severe thunderstorms producing heavy rain and hail… Either washed out or damaged several County roads in the Watkins and Bennett areas. A small tornado (f0) touched down near Bennett…but did no damage. Hail as large as 1 3/4 inches in diameter fell near Watkins. One inch diameter hail was measured near Hudson and Keenesburg.

In 2008…strong winds blew several trees down in Denver… Damaging homes and downing power lines. A peak wind gust of 67 mph occurred at Centennial Airport…with gusts to 60 mph estimated in Denver. A peak wind gust of 37 mph was measured at Denver International Airport. An elderly man was killed when a wind damaged tree broke free and crushed him while he attempted to remove it. The downed power lines caused outages to about 500 Xcel Energy customers.

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In 1876…grasshoppers were in great abundance in the city and caused considerable damage to gardens and to crops in the surrounding farms and ranches.

In 1951…heavy thunderstorms rumbled across metro Denver through the night. Heavy rain totaled 3.45 inches at Stapleton Airport. This was the greatest 24 hour precipitation ever recorded during the month of August in Denver.

In 2007…heavy rain caused localized flash flooding near Ft. Lupton. Up to 8 inches of water was reported across County Road 18. In addition…several other County roads in the immediate area were washed out.

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In 1878…the high temperature climbed to 100 degrees in downtown Denver.

In 1900…a thunderstorm produced west winds sustained to 48 mph with gusts to 55 mph…but only a trace of rain.

In 1903…a thunderstorm produced a trace of rainfall and northwest winds sustained to 45 mph with gusts to 60 mph. The high temperature was 99 degrees.

In 1927…a thunderstorm produced hail and sustained north winds to 22 mph.

In 1933…heavy cloudburst rains caused the failure of the Castlewood Dam…which resulted in flash flooding on Cherry Creek…the deaths of 7 people in Denver…and flood damage estimated at 1 million dollars. Lower Denver was flooded during the morning by waters pouring down Cherry Creek and its valley from Castlewood Dam…which had broken between midnight and 2:00 am. Heavy rain of 3 to 9 inches in 9 hours in the watershed above the dam resulted in the failure. At 7:30 am…the flow in Cherry Creek was reported at 16 thousand second-feet as compared with a peak flow of 3 thousand second-feet in other years. The flood waters ruined hundreds of acres of crops and drowned scores of farm animals. Six bridges in Denver were swept away. Great deposits of mud were left in the lower sections of the city…including hundreds of basements and lower floors of buildings. At the end of the month…a deadly stench still rose from swampy areas near the lower city limits.

In 1963…heavy thunderstorm rains in the Parker area caused Cherry Creek to overflow…which damaged roads.

In 1985…a tornado touched down briefly about 10 miles northeast of Parker. No damage was reported.

In 1991…upslope northeast winds produced chilly temperature readings and heavy rain across metro Denver. Rainfall… With no thunder…totaled 1.56 inches at Stapleton International Airport where the heavy rain briefly reduced the surface visibility to 7/8 mile. The mercury climbed to a high of only 63 degrees.

In 1992…a thunderstorm wind gust to 64 mph was recorded in Brighton. A wind gust to 60 mph was measured near the construction site of the new Denver International Airport. Lightning started a fire in an Evergreen church…causing over 75 thousand dollars in damage.

In 1998…3/4 inch hail fell in Jefferson County 15 miles northwest of Arvada.

In 2006…heavy thunderstorm rainfall caused flash flooding along Leyden Creek in unincorporated Jefferson County. An automated rain gauge on upper Leyden Creek…6 miles northwest of Arvada…measured 2.68 inches of rainfall in less than 2 hours. Two to three feet of water covered the roadway at the intersection of 82nd and Quaker Street.

In 2009…a woman riding her bike…in training for an ironman triathlon…was struck by lightning in Boulder. She was in the 78th mile of a 100-mile training ride when she was hit. The woman lost her vision initially and couldn’t move her arms. After a short stay in the hospital…she made of complete recovery.

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In 1988…two inches of rain fell in 3 hours at both Morrison and wheat ridge. Thunderstorm rainfall totaled 0.80 inch overnight at Stapleton International Airport.

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In 1889…southwest winds were sustained to 42 mph with an extreme velocity to 52 mph.

In 1924…0.01 inch of rain fell over downtown Denver. This along with the 0.01 inch of rainfall on the 10th was the only rainfall of the month…the driest August on record.

In 1963…heavy rains in the foothills above Idaho Springs caused mud and rock slides which closed U.S. Highways 6 and 40 for a time.

In 1976…hail to 1 inch diameter was reported 12 miles southwest of Denver. Hail to 3/4 inch in diameter was reported in Lakewood. Small hail…1/4 to 1/2 inch in diameter…fell at Stapleton International Airport.

In 1982…heavy rain poured through the roof of a clothing store in Aurora…causing widespread water damage. The roof was being repaired when the storm hit.

In 1983…hail up to one inch in diameter fell in Aurora where heavy rain produced street flooding.

In 1984…a Colorado state trooper was struck and injured by lightning in Northglenn.

In 1989…a microburst wind gust to 52 mph was recorded at Stapleton International Airport.

In 1997…lightning sparked a small fire in a home in Arvada… Causing minor damage. Several intersections in both Arvada and Westminster were flooded by thunderstorms producing heavy rain. Several cars were damaged by the high waters… And a number of businesses were flooded.

In 1999…flooding and flash flooding problems developed over metro Denver as slow moving thunderstorms dumped from 2 to 3.5 inches of rainfall in about 3 hours. Near the junction of I-25 and U.S. Highway 36…up to 4 feet of water flooded an auto dealership. About 45 cars were ruined. Damage estimates to the dealership alone totaled nearly a half million dollars. Sections of I-25 and U.S. 36 near the interchange were closed due to floodwaters. Floodwaters… Up to 5 feet deep…forced the evacuation of two mobile home parks in Federal Heights. Railroad tracks were washed out near Federal Blvd. and 64th Avenue. Numerous power outages caused widespread blackouts in Thornton and Littleton. Along Massey Draw near Carr St. And Chatfield Reservoir…4 homes were flood damaged and portions of their backyards washed out. Widespread street flooding was also reported in Boulder where several buildings were flood damaged…including the University of Colorado memorial center.

In 2004…two golfers were shocked when lightning struck the eighth green of the golf course at castle pines north of Castle Rock. The two men suffered only minor injuries. Heavy thunderstorm rain from the same storm caused flash flooding. Floodwaters rushed across parts of U.S. Highway 85 near the entrance to the Castle Pines golf club. The traffic lanes were covered with up to 6 inches of running water.

In 2008…lightning sparked a grassfire that consumed 300 acres on the northern edge of Green Mountain…in Jefferson County. Gusty winds and very dry conditions allowed the wildfire to quickly spread and threaten several houses. Fortunately…only minor damage was reported to homes due to smoke and melted siding.