Public Information Statement
Issued by NWS Denver/Boulder, CO

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NOUS45 KBOU 160859

Public Information Statement
National Weather Service Denver/Boulder CO
259 AM MDT SAT SEP 16 2017

...Today in metro Denver weather history...

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.
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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