849
NOUS45 KBOU 080045
PNSBOU
COZ030>051-082300-

Public Information Statement
National Weather Service Denver/Boulder CO
645 PM MDT SAT SEP 7 2024

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

        agricultural buildings were damaged just west of State
        Highway 79.
      In 1978...high winds produced much blowing dust...causing many
        traffic accidents in the Denver-Boulder area.  Winds gusts
        of 70 to 101 mph were recorded.  Northwest winds gusted to
        44 mph at Stapleton International Airport.
      In 1980...lightning hit two power poles in Littleton...causing
        400 dollars in damage.  Rainfall of 1.23 inches in a short
        time caused minor flooding...which included damage to a
        ground floor apartment and partially submerging a few
        vehicles in water.  Thunderstorm rainfall totaled 0.98 inch
        at Stapleton International Airport.
      In 1983...2.10 inches of rain drenched Golden in an hour with
        similar amounts in Lakewood and Boulder.  Over ten thousand
        dollars worth of plants were washed away at a nursery in
        Lakewood.
      In 1997...twelve motorists were injured in a multi-car
        accident when strong microburst winds estimated to 50 mph
        blew blinding dust across I-70 near Bennett.
      In 1998...lightning struck a hydro-electric plant in Nederland...
        causing a power outage.  Residents in the foothills west
        of Boulder...including Nederland...Ward...Eldora...Jamestown...
        and Gold Hill...were without power for about an hour.
      In 2006...heavy thunderstorm rainfall near Deckers washed
        away some the banks along State Highway 67 between Deckers
        and Westcreek.  Several driveways on both sides of the
        highway were also damaged.
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.
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.
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.
8     In 1886...the last thunderstorm of the season pelted the
        city with hail the size of beans and dropped 0.81 inch of
        precipitation.
      In 1962...the earliest first freeze of the season occurred.
        The temperature dipped to a low of 31 degrees.
      In 1973...hail up to 1 1/2 inches in diameter fell northeast
        of Boulder.  A tornado was reported by a pilot east of
        Parker.  No damage was reported.
9     In 1933...heavy rain in the foothills over the Clear Creek
        and Golden Gate canyon watersheds caused flooding in
        Golden and damaged the roadway in Golden Gate Canyon...
        which resulted in its closure.
      In 1969...a funnel cloud was sighted in southeast Denver.
        There was also considerable thunderstorm activity and
        local heavy rain across metro Denver.  Rainfall totaled
        1.30 inches at Stapleton International Airport where small
        hail also fell.
      In 1973...hail from 3/4 inch to 1 3/4 inches in diameter fell
        in Westminster and south of Broomfield.
      In 2009...A man was critically injured when he was struck by
        lightning while riding his bicycle.  He was nearing a
        paramedic van when he was hit.  His heart stopped but
        paramedics quickly responded and were able to resuscitate
        him.
      In 2011...A man was struck by lightning at the Adams County
        Fairgrounds.  He was leaning against a tree while watching
        a cross country meet when the tree was hit.  The lightning
        traveled down the tree and up through the ground...using
        him as a conductor.  The victim received second and third
        degree burns.
9-10  In 1933...heavy rain over the Cherry Creek...Plum Creek...Big
        Dry Creek...and Little Dry Creek watersheds caused flooding
        on the South Platte River in Denver overnight.  Nearly an
        inch of rain...0.98 inch...fell in the city.
      In 1944...a trace of rain fell on each day.  This together
        with a trace of rain on the 4th 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 1994...unusually very warm weather resulted in three
        temperature records being equaled.  High temperatures
        of 94 degrees on the 9th and 93 degrees on the 10th
        equaled record maximums for the dates.  Low temperature
        of 63 degrees on the 9th equaled the record high minimum
        for the date.
10    In 1985...golf ball size hail was reported just east of Parker.
      In 1989...3/4 inch diameter hail fell in Littleton.  Heavy rain
        produced local flooding in Lakewood.  The heavy rain caused
        the wall of a house to collapse.
      In 1993...thunderstorm winds downed power lines...which caused a
        power outage in Castle Rock.
10-17 In 2018...the high temperature equalled or exceeded 90 degrees for
        8 consecutive days; breaking the previous streak of 7 consecutive
        days in the month of September.
10-18 In 2018...the high temperature equalled or exceeded 90 degrees for 9
        consecutive days; marking the first time such an occurrence has
        taken place in the month of September.  It also brought September
        of 2018 into a 4-way tie for most 90 degree + days in the month.
        Previous years included 2017...2005 and 1895. During the streak...4
        record high temperatures were either tied or broken...and one
        record high minumum temperatures was broken.
11    In 1910...west winds were sustained to 42 mph.
      In 1951...a vigorous Canadian cold front produced a dust storm
        across metro Denver.  Northeast wind gusts to 43 mph reduced
        the visibility at Stapleton Airport to as low as 1 1/2 miles
        for nearly 5 hours.  The temperature dropped 47 degrees in
        8 hours...from a high of 92 degrees to a low of 45 degrees.
      In 1967...a microburst wind gust to 52 mph produced blowing
        dust and briefly reduced the visibility to 1/2 mile at
        Stapleton International Airport.
      In 1974...a trace of snow...the first of the season...ended
        the shortest period without snow...94 days from June 9th
        through September 10th.  A trace of snow also fell on
        June 8th.
      In 1995...strong post-frontal winds associated with a fast
        moving Pacific cold front knocked down power poles and trees
        as it moved through metro Denver.  Numerous power outages
        affected nearly one thousand people in Denver and Jefferson
        counties.  West winds gusted to 34 mph at Denver
        International Airport.
11-16 In 2013...a deep southerly flow over Colorado...ahead of a
        nearly stationary low pressure system over the Great Basin...
        pumped copious amounts of monsoonal moisture into the area.
        In addition...a weak stationary front stretched along the
        Front Range Foothills and Palmer Divide.  This resulted in
        a prolonged period of moderate to heavy rain across the
        Front Range Foothills...Palmer Divide...Urban Corridor. By
        the 14th...storm totals ranged from 6 to 18 inches...highest
        in the foothills of Boulder County. The headwaters then
        moved down the South Platte River and caused widespread
        flooding with record flood stages at several locations as
        it made its way downstream.  The record high flood stages
        resulted in widespread flooding along the South
        Platte River Basin. The flood damage encompassed 4500
        square miles of the Front Range...left 7 dead...forced
        thousands to evacuate...and destroyed thousands of homes
        and farms. Record amounts of rainfall generated flash
        floods that tore up roads and lines of communication...
        leaving many stranded. Nearly 19000 homes were damaged...
        and over 1500 destroyed. Colorado Department of
        Transportation estimated at least 30 state highway bridges
        were destroyed and an additional 20 seriously damaged.
        Preliminary assessments of the state`s infrastructure
        showed damage of $40 million to roads and $112 million to
        bridges. Repair costs for state and and county roads ran
        into the hundreds of millions of dollars. Miles of freight
        and passenger rail lines were washed out or submerged...
        including a section servicing Amtrak`s iconic California
        Zephyr. The town of Lyons was isolated by the flooding
        of St. Vrain Creek...and several earth dams along the
        Front Range burst or were over-topped. Floodwaters swept
        through Estes Park; damaged hundreds of buildings and
        destroyed large sections of U.S. 34 from Loveland and U.S.
        36 from Lyons to Boulder. U.S. 34 suffered the most damage...
        with 85 percent of its roadway and bridges destroyed. In
        Weld County...about nearly two thousand gas wells were
        damaged and had to be closed off as the floodwaters
        inundated entire communities. Sewage treatment plants and
        other utilities were knocked out in a number of towns.
        Governor Hickenlooper declared a disaster emergency on
        September 13th...in 11 counties across northeast Colorado
        including:  Adams...Arapahoe...Broomfield...Boulder...Denver...
        Jefferson...Larimer...Logan...Morgan...Washington and Weld. By
        the 15th...federal emergency declarations covered those
        counties as well as Clear Creek County. Projected losses
        from the flooding statewide was nearly two billion dollars
        in property damage...according to Eqecat...a catastrophe
        modeling firm.  The damage was most severe in and around
        Lyons and Boulder.  More than 11 thousand people were
        evacuated...reportedly the largest since Hurricane
        Katrina. President Obama declared a state of emergency
        for Boulder and Larimer Counties.  An additional 10
        counties were added on the 16th and included: Adams...
        Arapahoe...Broomfield...Clear Creek...Denver...Jefferson...
        Morgan...Logan...Washington and Weld Counties. The
        president also declared a major disaster specifically
        for Boulder County.  There were six fatalities
        directly attributed to flash flooding. Two 19-yr old
        teenagers died on the 11th...after they were swept
        away by floodwaters after abandoning their car on
        Lindon Drive in Boulder. In Jamestown...a 72-yr old
        man was killed when the building he was in collapsed.
        An 80-yr old Lyons resident died in the early morning
        hours of the 12th...when his truck was swept into the
        St. Vrain River near his home. Later on the 12th...a
        79-yr old Larimer County resident was killed when she
        was swept away while trying to climb to safety from
        her home in Cedar Point. A 61-yr old Cedar Point
        resident died when her home was swept down the Big
        Thompson River by the floodwaters. An 80-yr old
        Idaho Springs resident drowned in Clear Creek when
        the embankment he was standing on collapsed. In
        Boulder...some of the monthly records broken included:
        one-day all-time record: 9.08 inches which shattered
        the previous wettest day of 4.8 inches set on July 31...
        1919; one-month record of 18.16 inches...which broke
        the previous all-time monthly record of 9.59 inches set
        in May of 1995; wettest September on record which broke
        the previous record of 5.5 inches set in September of
        1940; one-year record of 34.15 inches broke the previous
        wettest year of 29.93 inches set in 1995. At Denver
        International Airport...the total precipitation for the
        month of September was 5.61 inches...which was 4.65
        inches above the normal of 0.96 inches. This is the most
        precipitation ever recorded in Denver for the month of
        September. Daily precipitation records included 1.11
        inches on the 12th and 2.01 inches on the 14th.
11-12 In 1974...post-frontal rain changed to snow overnight for the
        first snow of the season.  Snowfall totaled only 1.8 inches
        at Stapleton International Airport where north winds gusted
        to 40 mph on the 11th.  High temperature of only 46 degrees
        on the 12th set a new record low maximum for the date.
12    In 1887...west winds to 42 mph were recorded in the city.
      In 1952...a thunderstorm outflow produced strong southeast
        winds gusting to 52 mph.  Surface visibility at Stapleton
        Airport was briefly reduced to 2 miles in blowing dust.
      In 1963...a nearly stationary...white tornado near Bennett was
        sighted from Denver.  No damage was reported.
      In 1989...an early snowfall and the first of the season
        brought 2 to 3 inches of slush to metro Denver.  More snow
        whitened the foothills west of Denver where 6 inches were
        measured at Evergreen.  The snow fell on leaf laden trees...
        and sagging branches onto power lines caused outages.  Much
        of Denver`s snow fell during the evening rush hour...creating
        traffic chaos.  Snowfall totaled 2.3 inches at Stapleton
        International Airport where the maximum snow depth on the
        ground was only 1 inch due to melting.
      In 1994...thunderstorm microburst winds gusted to 67 mph in
        Boulder.  No damage was reported.
      In 2002...a severe thunderstorm produced hail as large as
        1 inch in diameter near Castle Rock.
13    In 1899...west winds were sustained to 43 mph with gusts to
        46 mph.
      In 1928...northwest winds were sustained to 41 mph with gusts
        to 45 mph.
      In 1937...an apparent dry microburst produced brief north winds
        sustained to 31 mph with gusts to 41 mph.  There was a trace
        of rain.
      In 1982...torrential rains drenched both the foothills and
        plains from Denver north.  While the heaviest rain occurred
        north of Denver...just east of Denver 2 1/3 inches of rain
        fell in 5 hours along with hail that caused minor damage to
        a few airplanes.  Thunderstorm rainfall totaled 0.83 inch
        at Stapleton International Airport.
      In 1993...an upper level system combined with a cold and moist
        upslope flow to bring the heaviest snowfall to metro Denver
        for so early in the season.  Snowfall from the storm totaled
        5.4 inches at Stapleton International Airport; however...most
        of the snow melted as it fell leaving a maximum of one inch
        on the ground at any one time.  North winds gusted to 21 mph
        at Stapleton International Airport where a record low
        temperature of 33 degrees for the date was observed.
      In 2002...Friday the 13th proved to be bad luck for several
        motorists when heavy thunderstorm rainfall caused flooding
        on I-25 in central Denver.  Water rose several feet under
        the Logan Street overpass...inundating several vehicles.
        Some motorists were rescued...while others simply waited atop
        their cars for the flood water to recede.  The highway had
        to be closed in both directions for about 3 hours.  The
        flooding was exacerbated by poor drainage due to the
        construction along the highway.  A 12-foot drainage pipe
        had not yet been installed beneath the underpass.  The
        deluge also flooded several businesses along Broadway.
      In 2009...a severe thunderstorm produced large hail...up to
        half dollar size in the foothills of Jefferson County...
        west of Denver.
14    In 1912...snow fell for most of the day...but melted as it fell.
        Precipitation from melted snow was 0.46 inch.  Some sleet was
        also observed.  Total precipitation was 0.61 inch.  North
        winds were sustained to 15 mph with gusts to 17 mph.
      In 1934...a moderate dust storm blew into the city at 4:15 PM.
        North winds were sustained to 35 mph with gusts to 44 mph.
        By 5:25 PM the winds had decreased and the storm had ended.
        A trace of rain fell during the evening.
      In 1976...a tornado touched down just west of I-25 between
        Arapahoe Road and Dry Creek Road...tearing the roof from a
        house.  Nearby...a high tension wire fell on a house causing
        damage...and lightning ripped a hole in the side of a house.
        Three tornadoes were observed just east of Stapleton
        International Airport and northeast of Buckley Field.  No
        damage was reported.  Dime to quarter size hail fell in
        northeast Denver with only 1/4 inch hail at Stapleton
        International Airport.  The Colorado State Patrol reported
        golf ball size hail 4 miles west of Franktown.  A funnel
        cloud was sighted 4 miles north of Franktown.
      In 1983...a thunderstorm produced winds gusts as high as 56
        mph across metro Denver along with thick blowing dust.
        Power was knocked out in many locations.  Thunderstorm winds
        gusting to 49 mph briefly reduced the visibility to 2 miles
        in blowing dust at Stapleton International Airport.
      In 1996...a 54-year-old woman was struck by lightning near
        Franktown...as she was preparing an outdoor barbeque.  The
        woman was knocked unconscious...but received only minor
        injuries.  Thunderstorms over southern Jefferson County
        dumped heavy rain in the Buffalo Creek area.  Some minor
        roads were washed out by flash flooding...but no other
        damage was reported.  Hail ranging in size from 1/2
        to 3/4 inch in diameter fell at the site of the former
        Stapleton International Airport.
      In 2006...a microburst from a thunderstorm produced
        sustained winds to 40 mph with gusts to 53 mph at
        Denver International Airport.

$$