570
NOUS45 KBOU 150045
PNSBOU
COZ030>051-152300-

Public Information Statement
National Weather Service Denver/Boulder CO
645 PM MDT SAT SEP 14 2024

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

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.
11-16 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.
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
        observed.
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.
17    In 1873...brisk west to northwest winds at different times
        during the day...generally in sudden gusts...spread a good
        deal of dust into the city.
      In 1953...strong winds caused thousands of dollars in damage
        to Boulder.  The winds blew for most of the day with great
        gustiness...and a freak twister was reported during the
        afternoon.  Damage was minor.  A thunderstorm wind gust
        to 40 mph caused some blowing dust at Stapleton Airport.
      In 1992...a tornado touched down briefly near Bennett.  No
        damage was reported.
      In 1993...severe thunderstorms rumbled across northern
        portions of metro Denver.  Hail as large as 1 3/4 inches
        in diameter fell in Brighton.  Dime size hail damaged
        several roofs of residences in Lafayette.
      In 2000...for the second day in a row...the high temperature
        of 95 degrees at Denver International Airport broke three
        record temperature extremes:  the high temperature broke
        the previous record for the day of 94 degrees set in 1895;
        it marked the warmest it has been for so late in the season;
        it also marked the 61st day in the year that the temperature
        had equaled or exceeded 90 degrees...eclipsing the record
        equaled the previous day and first set on September 29...
        1994.
18    In 1901...northeast winds were sustained to 42 mph with gusts
        to 50 mph behind an apparent cold front.
      In 1948...the low temperature cooled to only 69 degrees...the
        all-time record high minimum for the month.
      In 1988...a strong cold front blasted metro Denver with
        high winds.  Gusts reached 82 mph in Longmont and 81
        mph at Jefferson County Airport near Broomfield where
        the winds flipped over and destroyed a small airplane.
        Wind gusts to 60 mph were recorded in Boulder and Wheat
        Ridge.  West wind gusts to 54 mph were clocked at Stapleton
        International Airport.  The strong winds downed trees and
        power lines and damaged homes and cars.  A Longmont man was
        slightly injured...when a tree fell on top of his car.
      In 1990...a slow moving thunderstorm over southwest metro
        Denver spawned an ominous looking funnel cloud near the
        intersection of Sheridan Blvd. and U.S. Highway 285.  The
        funnel cloud nearly touched down a few times before lifting
        back into the main cloud.  No damage was reported.  Pea to
        marble size hail and 3/4 inch of rain fell over central and
        northeast Denver.  Numerous streets and underpasses became
        flooded on Denver`s south side when the heavy runoff
        backed up storm sewers.  Thunderstorm rainfall totaled
        1.02 inches at Stapleton International Airport.
      In 1993...a severe thunderstorm rolled through southeast metro
        Denver.  Dime size hail was reported in many areas.
        Straight-line winds from the thunderstorm...measured by a
        weather spotter at 70 mph...tore the roof off 6 apartments
        of an apartment complex in Aurora.  Heavy rain which
        accompanied the winds caused major damage to the
        apartments as well as the contents.  Many trees...fences...
        and power poles were knocked down by the strong winds.
        Heavy rain flooded roadways in Denver and Aurora.
        Thunderstorm rainfall totaled 1.08 inches and north winds
        gusted to 44 mph at Stapleton International Airport where
        the visibility was briefly reduced to as low as 1/4 mile
        in heavy rain.
      In 1996...a late summer snowstorm struck the northern
        mountains and Front Range eastern foothills.  Golden
        Gate Canyon received 6 inches of new snow with 5 inches
        reported at both Nederland and Blackhawk.  Thunderstorms
        produced heavy rain across metro Denver...which was mixed
        with snow by late evening.  Rainfall totaled 0.83 inch
        at the site of the former Stapleton International Airport
        and 1.22 inches at Denver International Airport where
        northwest winds gusted to 39 mph.
18-19 In 1955...heavy rains caused flash flooding across portions of
        metro Denver.  Rainfall totaled 1.71 inches at Stapleton
        Airport.
19    In 1955...hail stones to 2 1/2 inches in diameter were
        reported north of Denver.  The large stones broke many
        automobile windshields.
      In 1963...hail to 3/4 inch in diameter fell in Westminster.
      In 1983...an unusually strong cold front roared through
        metro Denver during the afternoon hours.  At Stapleton
        International Airport...the temperature dropped 51 degrees...
        from a sunny 86 degrees to a snowy 35 degrees...in just 7
        hours.  Strong winds and a wall of blowing dust followed
        the front.  Northeast winds gusting to 36 mph briefly
        reduced the surface visibility to 1 mile in blowing dust
        at Stapleton International Airport where only a trace of
        snow fell later.
      In 1996...high winds gusting to 84 mph were measured at
        Golden Gate Canyon in the foothills west of Denver.
        West winds gusted to only 25 mph at Denver International
        Airport.
20    In 1921...an apparent bora produced northwest winds sustained
        to 44 mph with gusts to 64 mph.
      In 1955...hail stones 1/2 to 3/4 inch in diameter were
        reported across parts of the City of Denver.
      In 1992...weather observers at Buckley Air National Guard Base
        sighted two tornados southeast of the base.  The tornados
        were short-lived and caused no injuries or damage.
20-21 In 1963...heavy rain and hail caused local flooding in
        southeast Denver.  Thunderstorm rainfall was only
        0.60 inch at Stapleton Airport on the 20th.
      In 1983...the cold front on the 19th brought an unusually cold
        air mass into metro Denver for so early in the season.  The
        temperature dipped to a daily record minimum of 28 degrees
        on both days.
      In 1995...a vigorous late summer storm brought the season`s
        first heavy snow to portions of metro Denver.  Millions
        of trees were damaged and power lines downed as 4 to 8
        inches of heavy wet snow settled on fully leafed trees in
        the Boulder and Denver areas.  Branches snapped and trees
        split under the weight of heavy snow...downing power lines.
        Firefighters responded to numerous transformer fires.
        Around 100 thousand people were left without electricity
        in Boulder and Denver areas alone.  It took over a week
        to fully restore power to some areas.  Insurance claims
        were estimated to be around 6 million dollars to homes
        in metro Denver and about 500 thousand dollars in damage
        to automobiles.  It was estimated that about 80 percent
        of 125 million dollars worth of city owned trees in Denver
        were damaged.  Snowfall totaled 7.4 inches at the site of
        the former Stapleton International Airport where the
        greatest depth of snow on the ground was only 4 inches
        due to melting.  Temperature records were set on the
        21st when the thermometer dipped to a record low reading
        of 27 degrees and climbed to a high of only 36 degrees...
        setting a record low maximum for the date.  North winds
        gusted to 29 mph at Denver International Airport on the
        20th.
20-22 In 1902...a thunderstorm on the 20th...in advance of an
        apparent cold front...produced rain...hail...and northwest
        winds to 40 mph with gusts to 48 mph.  Widespread rain
        developed behind the cold front and totaled 3.21 inches
        from the evening of the 20th through the early afternoon
        of the 22nd.  The 2.70 inches of precipitation recorded
        from 800 PM on the 20th to 800 PM on the 21st is the
        greatest 24 hour precipitation ever recorded in the
        month of September.  The temperature dipped from a high
        of 80 degrees on the 20th to a high of only 51 degrees
        on the 21st.
21    In 1951...4.2 inches of snow fell at Stapleton Airport...
        where northeast winds gusted to 27 mph.  This was the
        first snowfall of the season in Denver...marking the end
        of the second shortest snow-free period on record...109
        days...from June 4th through September 20th.  A trace of
        snow fell on June 3rd.
      In 1984...thunderstorm winds gusted to 56 mph at Stapleton
        Airport.
      In 1992...the only precipitation of the month at Stapleton
        International Airport...0.01 inch of rain...fell from a
        brief shower around daybreak.
      In 2009...an early season storm brought moderate to heavy
        snow to the foothills of Clear Creek...Jefferson and Park
        Counties...west and southwest of Denver.  A trained
        spotter...4 miles west-northwest of Conifer...was the big
        winner with 14 inches of snow.  Storm totals elsewhere
        generally ranged from 5 to 10 inches.
21-22 In 1870...strong winds occurred in the foothills and in
        Boulder and Denver.
      In 1895...rain changed to snow overnight and totaled 11.4
        inches in downtown Denver.  This was the first snowfall
        of the season and the second heaviest first snowfall of
        the season on record.  North winds were sustained to 27
        mph with gusts to 30 mph on the 21st.

$$