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Public Information Statement
National Weather Service Denver/Boulder CO
645 PM MDT SAT AUG 31 2024

...This week in metro Denver weather history...

1     In 1951...large hail pounded Boulder...causing thousands of
        dollars in damage to roofs and automobiles.  Heavy
        thunderstorm rainfall flooded basements and produced
        widespread street flooding.
      In 1966...severe thunderstorms caused local flooding in areas
        from Denver to the north and east.  There was scattered
        damage from hail and lightning.  Streets were flooded in
        Boulder...and streets and basements were flooded in several
        areas of metro Denver.  The public reported 1 inch
        diameter hail in Aurora and near Cherry Creek Reservoir.
        Thunderstorm rainfall totaled only 0.39 inch at Stapleton
        International Airport.
      In 1985...severe thunderstorms dumped heavy rain and hail at
        many locations along the Front Range from Denver south.
        The southern and eastern suburbs of metro Denver were
        especially hard hit.  Rainfall from 1 1/2 to 3 inches
        caused extensive street flooding in Aurora where two
        creeks rose out of their banks.  Two homes in the city
        suffered minor lightning damage.  Almost 4 inches of rain
        fell in the Parker area.  Hail up to ping-pong ball size
        piled up to a foot deep and closed a road in Evergreen.
        Hail as large as 1 3/4 inches in diameter was reported
        8 miles northeast of Deckers.  Wind gusts to 65 mph were
        estimated in southeast Aurora.
      In 1990...marble size hail piled up to 2 inches deep in the
        foothills community of Kittredge...18 miles southwest of
        Denver.  As much as half an inch of rain fell in just 15
        minutes and caused minor road and small stream flooding.
        A thunderstorm dropped pea to marble size hail and brief
        heavy rain near Ward Road and 64th Avenue in Arvada.
        Minor street and small stream flooding was reported in
        the area.
      In 1995...a strong thunderstorm microburst with only a few
        drops of rain produced a recorded wind gust to 85 mph at
        the site of the former Stapleton International Airport.
        The wind gust occurred at 8:30 PM MDT.  The all-time
        highest recorded temperature in September...97 degrees...
        occurred.  The same temperature also occurred on
        September 5...1899...September 4...1960...and September 4...
        1995.
      In 2019...the high temperature in Denver reached 98 degrees...
        which not only broke the record for the date...but also
        set a new monthly record for the month of September.
1-5   In 1995...record breaking heat occurred on the first 5 days
        of the month when the temperature climbed into the 90`s
        on each day.  Record high temperatures of 97 degrees on
        both the 1st and 4th equaled the all-time record maximum
        for the month.  High temperature of 95 degrees on the 3rd
        was a record for the date.  High temperatures of 94 degrees
        on both the 2nd and the 5th were not records.  The low
        temperature of 64 degrees on the 4th equaled the record
        high minimum for the date.
1-7   In 1978...the temperature reached 90 degrees or more on seven
        consecutive days with the highest temperature...94 degrees...
        recorded on both the 4th and 6th.
1-30  In 2020...a worsening drought that started in the spring and
        continued through September. Outside of an early season
        snow on the 8th...the month of September was another
        unseasonably warm and dry period. The combination
        of hot...mostly dry conditions...and critically dry fuels...
        resulted in a continuation and rapid expansion of several
        massive wildfires. The Cameron Peak fire...which became the
        largest in the state`s history started on August 13th...and
        continued through September. As a result...very poor air
        quality continued to impact Denver and the entire Front
        Range.  Denver recorded the most days ever with a high
        temperature of 90 degrees or better; 75 days.  The last
        of which was 91 degrees on the 24th.  The previous
        record was 73 days set in 2012.
2     In 1938...heavy cloudbursts in the foothills near the top of
        Genesee Mountain caused flash flooding on Bear Creek at
        Morrison.  Nearly 8 inches of rain fell just north
        of Morrison in 6 hours and drowned 6 people in a car
        between Morrison and Kittredge.  Damage was estimated at
        nearly a half million dollars.  Flash flooding also
        occurred on South Boulder Creek in Eldorado Springs.
        Rainfall totaled 4.42 inches in Eldorado Springs...and
        rainfall was estimated to more than 6 inches in the
        foothills west of the town.  Many buildings and residences
        were damaged in Eldorado Springs...and bridges were swept
        away.  The high waters forced residents from their homes
        as far downstream as Erie.  This was the flood of record
        on South Boulder Creek.
      In 1973...hail to 3/4 inch diameter was reported in Boulder.
      In 1987...lightning struck two men who were standing under a
        tree in downtown Denver.  Both were seriously injured and
        hospitalized.
      In 1996...lightning sparked a brush fire in the south buffer
        zone of the Rocky Flats Environmental Test Facility.  No
        structures were damaged...but the fire burned about 100
        acres of grassland before being contained.
      In 2019...the record high temperature of 100 degrees was set
        in Denver...shattering the previous daily record of 95
        established in 1983.  Not only was the daily record set...
        it also set the all time monthly record for September.
        The previous record for the month was 98 degrees...which
        was set the previous day.  In addition...it was the latest
        100+ degree day ever reached during the calendar year in
        Denver`s climate record...breaking the previous mark by 17
        days.  The previous record occurred on August 16th...2002.
        Lastly...it was the hottest Labor Day on record.
2-3   In 1892...there was a trace of rainfall each day.  This...
        together with a trace of rain on both the 7th and 8th...was
        the only rainfall of the month...making the month the driest
        on record.  The monthly record was equaled in 1944.
3     In 1901...a thunderstorm produced rain...hail of unknown size...
        and south winds sustained to 40 mph with gusts to 43 mph.
      In 1961...the Labor Day weekend snow storm is the earliest
        date of the first snow...trace and measurable...of the season.
        The heavy wet snow broke many limbs from trees that were
        still in full foliage.  The storm produced 4.2 inches of
        snowfall at Stapleton Airport with nearly a foot of snow
        in western suburbs and in the foothills.  Minimum
        temperature of 33 degrees was a record for the date and the
        coldest ever recorded so early in the season.
      In 1999...severe thunderstorms dumped large hail across metro
        Denver.  Hail as large as 1 inch in diameter was measured
        near Cherry Creek in Aurora and near Bennett.  Hail to 3/4
        inch in diameter fell in the City of Denver.
      In 2002...a thunderstorm produced a wind gust to 51 mph at
        Denver International Airport.
      In 2003...very heavy thunderstorm rain washed out parts of
        the Virginia Canyon Road above Idaho Springs.  Up to
        4 feet of mud reportedly washed down the road during the
        storm.  Several vehicles were trapped on the road.  In
        Idaho Springs...several streets...including the main street...
        were also buried in mud and gravel.  Some buildings in
        town experienced minor flooding...including the basement
        of the town library and the police station.
3-6   In 1909...rainfall for the 4 days accumulated to 3.97 inches
        in Boulder...while in Denver rainfall totaled 2.45 inches
        on the 4th...5th...and 6th.
4     In 1909...apparent post-frontal heavy rainfall totaled 1.94
        inches in downtown Denver.  North winds were sustained
        to 19 mph.
      In 1944...a trace of rain fell.  This together with a trace
        of rain on the 9th...10th...and 30th was the only
        precipitation for the month.  The total of a trace of
        precipitation for the month equaled the driest September
        on record first set in 1892.
      In 1960...the highest recorded temperature in September...97
        degrees...occurred.  The same temperature also occurred on
        September 5...1899...September 1...1995...and September 4...
        1995.
      In 1989...a strong thunderstorm wind gust flipped a plane
        taxiing on a private runway in Adams County east of Denver.
        Two people were slightly injured and the plane was heavily
        damaged.
      In 1992...strong winds developed across metro Denver behind a
        Pacific cold front.  Sustained winds above 40 mph with gusts
        as high as 60 mph were recorded mainly in and near the
        foothills.  Pre-frontal south winds gusted to 37 mph at
        Stapleton International Airport.
      In 1995...two people were injured when lightning struck their
        home in Lakewood.  The lightning entered the attic where it
        started a small fire.  It then traveled through the walls...
        exploding a mirror and spraying glass on the residents.
        Lightning also sparked small grass fires near Aurora...Denver
        International Airport...and Bennett.  The highest recorded
        temperature in September...97 degrees...occurred.  The same
        temperature also occurred on September 5...1899...September
        4...1960...and September 1...1995.
      In 2000...thunderstorm winds gusted to 64 mph in Castle Rock.
5     In 1899...the highest recorded temperature in September...97
        degrees...occurred.  The same temperature was also reached on
        September 4...1960...and September 1 and 4...1995.
      In 1940...a severe wind and hail storm confined mostly to the
        west and north parts of the city occurred shortly after
        4:30 PM.  Hail stones ranged in size from 1/4 to 1/2 inch
        in diameter.  In north Denver...hail piled to a depth of
        4 inches.  Flooding occurred in one underpass...which
        stalled 2 cars.  One girl was injured when the weight
        of the hail flattened a porch on which she stood.
        Northeast winds were sustained to 29 mph with gusts to
        32 mph in downtown Denver.
      In 1987...a thunderstorm complex produced hail as large as
        1 3/8 inches in diameter...2 miles east of Buckley Field in
        Aurora.  No damage was reported.
5-8   In 2020...a strong upper level low brought an end to record
        heat to the Front Range urban corridor...and provided Denver
        its second earliest measurable snowfall on record. Numerous
        heat records were set leading up to the snowfall...and
        several new snowfall and cold records were also broken in
        this abrupt bout with winter.  Denver set its all time
        record high for September...reaching 101 degrees during the
        afternoon. This was also the latest date a 100 degree
        reading has ever been observed in Denver.  Another daily
        record high was then tied on September 6th when Denver hit
        97 degrees. September 7th was the last day of heat when
        Denver`s high temperature reached 93 degrees.  That tied
        Denver for the record for the number of 90 degree days for
        a year at 73...and was also the warmest temperature ever
        recorded before a day of measurable snowfall.  By the
        evening of September 7th...a series of cold fronts
        progressed southward from Wyoming into Colorado...
        dropping the temperature into the low 30s by the early
        morning hours of September 8th.  Snow developed across
        the Front Range mountains and foothills overnight...
        while a mix of rain and snow developed along the I-25
        corridor.  A few locations picked up light snowfall
        accumulations in the morning. Accumulating snow was
        mostly confined to the higher elevations much of the
        day...before spreading across the plains during the
        late afternoon and evening. Storm totals ranged from
        4 to 10 inches in the mountains...with 3 to 6 inches
        near the foothills.  A total of 5.6 inches of snow
        was measured at the NWS Boulder office...while at
        Denver International Airport...the official
        measurement was 1.0 inch.
5-9   In 1988...layers of smoke aloft from large forest fires in
        Yellowstone National Park completely obliterated the sun
        at times.  At Stapleton International Airport...surface
        visibility was reduced at times to 5 and 6 miles in smoke.
5-13  In 2010...the Fourmile Canyon Wildfire...northwest of Boulder...
        broke out on the morning of the 5th.  It originated from
        an unattended fire pit at a local residence. The wildfire
        quickly consumed 5 1/2 square miles or 3500 acres the
        first day...and forced the evacuation of over three
        thousand residents.  Erratic 45-mph gusts sent the fire in
        two directions at times. Very dry weather conditions
        preceded the fire. The combination of strong winds...low
        relative humidities and dry fuels allowed the wildfire
        spread rapidly through the steep...heavily forested terrain.
        The flames were reportedly 20 to 50 feet in length.  Towns
        within the burn area included Salina...Wallstreet and Gold
        Hill. The dry conditions coupled with gusty winds ranging
        from 45 to 64 mph persisted for several more days. Fire
        managers used as many as 700 firefighters and support
        personnel from 35 agencies and seven air tankers to battle
        the wildfire.  A total of 6181 square acres or
        approximately 10 square miles were burned.  The Fourmile
        Canyon Wildfire was the most destructive fire in Colorado
        history in terms of the damage to personal property.  It
        destroyed 171 homes with an estimated cost of 217 million
        dollars.
6     In 1940...a thunderstorm pelted the city with small hail.
        The storm produced some lightning damage.  One woman was
        stunned by a bolt which struck near her.  Heavy rain from
        the storm raised the level of Cherry Creek by more than
        3 feet during the height of the storm.  Rainfall downtown
        was only 0.26 inch.
      In 1988...strong winds blew down two houses that were under
        construction in Castle Rock.  Northwest winds gusted to 44
        mph at Stapleton International Airport.
      In 1993...a man was struck and killed by lightning while
        standing outside his home in unincorporated Arapahoe County
        11 miles south of Denver.  Lightning also struck a cabin in
        Marshdale...20 miles southwest of Denver...which started a
        fire and damaged one room and a portion of the roof.
      In 1995...hail as large as 3/4 inch in diameter fell in Coal
        Creek Canyon in northern Jefferson County.
      In 2001...a thunderstorm dropped 3/4 inch diameter hail in
        Aurora near Cherry Creek.
7     In 1875...the creeks were running dangerously high during
        the night from heavy rains in the mountains.
      In 1885...a thunderstorm produced very white hail of irregular
        shape and about the size of beans.  Precipitation was
        only 0.10 inch.
      In 1971...a vigorous cold front accompanied by a thunderstorm
        produced wind gusts to 48 mph at Stapleton International
        Airport and much upslope cloudiness and light rain across
        metro Denver.
      In 1989...widespread thunderstorms produced lightning strikes
        that knocked out power to about 13 thousand homes in Boulder
        County.  In a rugged area stripped of vegetation by a forest
        fire earlier in July...heavy rain triggered mud slides that
        destroyed one home and severely damaged another in Boulder
        Canyon 10 miles west of Boulder.  In one home...the mud
        caved in an exterior wall and poured into the residence
        only seconds after 2 people had evacuated the premises.
        Rainfall totaled 1 to 3 inches.  Hail 1 3/4 inches in
        diameter fell in Nederland...Idaho Springs...and Golden
        Gate Canyon.  Hail 1 inch in diameter was measured 10
        miles north of Golden.
      In 1993...thunderstorm winds toppled an overhead sign onto
        the intersection of I-70 and I-25 in Denver...causing
        considerable damage to 4 vehicles.  The winds also caused
        a police car to be blown off the road northeast of Denver.
        Thunderstorm winds gusting to 66 mph damaged the siding of
        a residence southeast of Brighton.  A thunderstorm wind
        gust to 53 mph was recorded at Stapleton International
        Airport.  Hail to 7/8 inch in diameter fell at Kittredge
        in the foothills of Jefferson County.
      In 1994...lightning severely damaged a public television
        transmitter atop Squaw Mountain west of Denver.
7-8   In 1884...a windstorm from mid-afternoon until the early
        morning hours of the 8th produced south winds sustained
        to 48 mph.  The strong winds toppled several trees in
        the city.
      In 1892...there was a trace of rainfall each day.  This
        together with a trace of rain on both the 2nd and 3rd was
        the only rainfall of the month...making the month the driest
        on record.  The record was equaled in 1944.

$$