Public Information Statement
Issued by NWS Denver/Boulder, CO

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NOUS45 KBOU 100045

Public Information Statement
National Weather Service Denver/Boulder CO
645 PM MDT SAT SEP 9 2017

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

        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
      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.
15    In 1899...a thunderstorm produced southwest sustained winds
        to 43 mph with gusts to 46 mph.
      In 1972...a pilot reported a funnel cloud briefly touching
        the ground in open fields...17 miles east-northeast of
        Stapleton International Airport.
      In 1980...thunderstorm winds gusted to 55 mph in Boulder.
      In 1982...brief heavy rain and winds estimated as high as 70
        mph occurred in the Conifer-Evergreen area.  No damage was
      In 1990...lightning triggered a small attic fire in a house
        near Sedalia...20 miles south of Denver.  A furious
        lightning storm caused widespread power outages across
        southern sections of metro Denver.  One lightning bolt
        knocked out an electrical substation...causing a 90-minute
        blackout in southeast Denver affecting nearly 10 thousand
        homes and businesses.
      In 2007...severe thunderstorms produced large hail...up to 2
        inches in diameter...near Larkspur.   Extensive damage to
        vehicles in the area was reported.  In Parker...lightning
        struck a residence.  The ensuing fire damaged the attic
        and top floor; causing $100000 in property damage.
      In least three homes were hit by lightning during
        the early morning hours in Arapahoe County.  Lightning
        also struck two homes in Castle Rock...damaging the roofs.
      In 2013...a dry microburst uprooted 30 to 40 large trees
        across a 12-block area of the Park Hill neighborhood in
        east central Denver. Several trees were snapped near the
        base along with numerous branches...8 to 10 inches in
        diameter. Power poles and lines were also downed with
        resulted in outages which affected seven hundred
        residents. One of the downed trees crushed a car`s hood...
        narrowly missing the driver. At Denver International
        Airport...a peak wind gust of 22 mph was observed from the
16    In 1902...a thunderstorm produced west winds sustained to
        48 mph with gusts to 60 mph...but only a trace of rain.
      In 1952...a thunderstorm wind gust to 50 mph was recorded at
        Stapleton Airport.
      In 1960...lightning struck a warehouse in central Denver...
        causing 8 thousand dollars in damage to the building and
        stored electrical equipment.
      In 1975...large hail...1 1/2 to 1 3/4 inches in diameter...fell
        about 4 miles north of Castle Rock.  Hail caused some minor
        damage in Aurora.  A funnel cloud was reported 25 miles
        east of Denver near Bennett.
      In 1981...a tornado touched down briefly in open country just
        to the east of Aurora.  No damage was reported.
      In 1982...a thunderstorm wind gust to 61 mph was recorded at
        Buckley Field in Aurora.  At the same time almost an inch
        of rain flooded and closed streets in south Aurora.  A
        women was hit by lightning just north of Denver.  A house
        in the area was also struck.
      In 1985...a thunderstorm produced strong wind gusts over
        southern metro Denver.  One strong wind gust hit Cherry
        Creek Reservoir...capsizing a boat and drowning a man.  The
        wind gusts...clocked as high as 50 mph...also downed a few
      In 1989...1 3/4 inch diameter hail fell at Intercanyon in
        the foothills of Jefferson County.
      In 1990...lightning caused minor damage to a south Aurora
        home.  No injuries were reported.
      In 1994...strong thunderstorm winds caused damage in southern
        Weld County near Hudson and Fort Lupton.  Two mobile homes
        were destroyed and a few lost their roofs.  Up to 20 downed
        power poles and the destruction of two 115 thousand-volt
        towers caused widespread power outages.  Thunderstorm gust
        front winds from the north gusted to 48 mph at Stapleton
        International Airport.
      In 2000...lightning ripped most of the roof from a home in
        southeast Aurora.  The bolt sparked a fire which destroyed
        the residence.  Damage was estimated at 250 thousand
      In 2002...the temperature climbed to a maximum of 100 degrees
        setting a new record high for the date.
      In 2003...a teenager was injured when he was struck by
        lightning while camping at Herman Lake...13 miles northwest
        of Georgetown.  The boy was knocked unconscious and suffered
        minor injuries.
16-19 In 1979...heavy thunderstorm rains on each of 4 consecutive
        days dumped a total of 2.62 inches of rain on Stapleton
        International Airport.  The heaviest rain...1.05 inches...
        on the 19th was accompanied by 1/4 inch diameter hail.
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
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 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.
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 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 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 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 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 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 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.
15    In 1921...rainfall of 0.02 inch was the only measurable
        precipitation of the month.
      In 1976...the public reported a funnel cloud and golf ball
        size hail east of Parker.
15-17 In 2000...unusually hot weather for so late in the season
        occurred when temperatures climbed into the 90`s setting
        daily record maximum temperatures on each of the 3 days.
        The high temperature was 92 degrees on the 15th and 95
        degrees on both the 16th and 17th.
15-19 In 1906...rain on 5 consecutive days totaled 1.61 inches.
        A thunderstorm occurred on the 17th.  High temperatures
        ranged from 48 degrees on the 16th to 65 degrees on the
        15th.  Low temperatures were in the lower to mid 40`s.
16    In 1874...a blast of west winds caused minor injuries during
        working hours in Boulder.  In Denver...the winds veered
        suddenly from the southwest to the northwest around noon
        and increased to a maximum sustained speed of 49 mph
        behind an apparent cold front.  The winds remained strong
        and backed to the west for the remainder of the afternoon.
      In 2000...the record high temperature of 95 degrees at Denver
        International Airport established or equaled 3 different
        record extremes:  the high temperature broke the previous
        record high for the day of 92 degrees set over a century
        ago in 1895; it marked the warmest that it has been so
        late in September; it also marked the 60th day during the
        warm season that the temperature had reached 90 degrees or
        more...equaling the record first set on September 29...1994.
      In 2006...strong bora winds behind a Pacific cold front
        raked the eastern slopes of the mountains and metro
        Denver during the afternoon.  Northwest winds were
        sustained to 40 mph with gusts as high as 54 mph at
        Denver International Airport.
      In 2007...a severe thunderstorm produced a peak wind gust
        of 67 mph...about one mile east of Bennett.  At Denver
        International Airport...a peak wind gust of 48 mph was
16-19 In 1971...a record breaking early fall snow storm caused
        extensive damage to trees and utility lines.  The heavy wet
        snow occurred with little wind...but caused record breaking
        cold temperatures for so early in the season.  Snowfall
        totaled 15.6 inches at Stapleton International Airport
        with most of the snowfall...12.0 inches...occurring on the
        17th.  This was the heaviest first snow of the season.
        The maximum snow depth on the ground was 13 inches.
        Record low temperatures were set on three consecutive days:
        31 degrees on the 17th...23 degrees on the 18th...and 20
        degrees on the 19th...which was also a new all-time record
        minimum for the month at that time.  Record low maximum
        temperatures were set on 4 consecutive days:  48 degrees
        on the 16th...35 degrees on the 17th...40 degrees on the 18th...
        and 42 degrees on the 19th.

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