Public Information Statement
Issued by NWS Denver/Boulder, CO

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COZ030>051-132300-

Public Information Statement
National Weather Service Denver/Boulder CO
645 PM MDT SAT MAY 12 2018

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

12-13 In 1907...from the 12th to the 13th...the temperature warmed to
        a high of 73 degrees on the 12th...before a cold front
        produced a thunderstorm...northeast winds sustained to 40
        mph...and rain changing to light snow overnight.  Snowfall
        totaled only 2 inches...but the high temperature on the 13th
        was only 39 degrees.
      In 1961...from the 12th to the 13th...a storm that covered
        metro Denver with rain and snow started as thunderstorms
        on the evening of the 12th.  Hail to 1 1/2 inches in
        diameter was reported 10 miles northwest of Stapleton
        Airport.  Rain continued overnight and changed to snow on
        the 13th.  Snowfall totaled 6.4 inches and precipitation
        (rain and melted snow) 1.96 inches at Stapleton Airport
        where north winds gusted to 39 mph.  The rain and heavy
        wet snow caused icing damage to utility lines.  Heavy
        snow occurred in the foothills.
      In 1982...from the 12th to the 13th...a major storm dumped
        1.50 to 3.50 inches of rain across northeast Colorado and
        deposited prodigious amounts of snow in the foothills. Coal
        Creek Canyon southwest of Boulder was buried under 46 inches
        of snow with 39 inches at Nederland.  The heavy wet snow
        downed many powerlines in the foothills.  In Thornton...the
        roof of a school was damaged by water from the heavy rain.
        At Stapleton International Airport...1.49 inches of rain
        were measured over the 2-day period.  The heavy rain ended
        a severe and prolonged drought.
      In 2004...from the 12th to the 13th...a winter storm produced
        heavy snow in excess of a foot in the foothills above 6
        thousand feet while heavy rain fell across the city.  The
        heaviest snow occurred in the high country of Boulder
        County. Storm total snowfall was 14.5 inches near Jamestown.
        Rainfall totaled 0.81 inch at Denver International Airport
        with 0.94 inch recorded at Denver Stapleton.  A trace of
        snow was recorded at both locations.  East winds gusted to
        24 mph at Denver International Airport on the 12th.
13    In 1905...a thunderstorm produced hail during the late
        afternoon.  Precipitation totaled 0.57 inch.
13-14 In 1912...from the 13th to the 14th...heavy snowfall totaled
        12.4 inches over the city. Most of the snow...9.9 inches...
        fell on the 13th...which was the greatest 24-hour snowfall
        in May at the time.  This was the last snowfall of the
        season.  The low temperature dipped to 27 degrees on the
        morning of the 14th.
      In 1989...from the 13th to the 14th...a spring storm brought
        heavy rain and snow to the foothills.  Metro Denver was
        soaked with 1 to 2 inches of rain.  Rainfall totaled 1.26
        inches at Stapleton International Airport.  In the
        foothills...Echo Lake received 20 inches of snow.  A 30-ton
        boulder slid onto I-70 east of the Eisenhower Tunnel...
        closing the freeway for 2 hours.
14    In 1910...a thunderstorm produced strong winds during the
        afternoon.  Northwest winds were sustained to 42 mph.
      In 1913...light moist snow and light hail fell during short
        intervals...although no thunder was heard.  The trace of
        snowfall was the only snow of the month.  Precipitation...
        mostly rain...totaled 0.44 inch.
      In 1984...a pilot reported a tornado 16 miles east of
        Stapleton International Airport.  No damage was reported.
        A thunderstorm produced a 58 mph wind gust in Brighton.
        Thunderstorm winds gusted to 48 mph at Stapleton
        International Airport.
      In 1989...lightning struck a home in Evergreen...setting it
        afire.
      In 1992...strong thunderstorm winds of unknown velocity...
        knocked over and damaged the infield tote board at
        Arapahoe Park racetrack just southeast of Aurora.
        Damage was estimated at 200 thousand dollars.  No
        injuries were reported.  Lightning started two house
        fires...causing 35 hundred dollars in damage in Adams
        County just 9 miles north-northwest of Denver.
      In 1994...a sudden wind gust...estimated at 40 mph...blew a
        portion of the roof off a shopping center in Lafayette.
        The roof also damaged two parked cars in an adjacent lot.
      In 2001...a construction worker in Castle Rock received minor
        injuries when lightning struck close-by.
      In 2002...a microburst wind gust to 53 mph was recorded at
        Denver International Airport.
      In 2007...severe thunderstorms producing large hail...very
        heavy rain...and tornadoes impacted the Urban Corridor and
        adjacent plains.  Heavy rain associated with a severe
        thunderstorm caused flooding along a small tributary
        draining into the South Platte River.  The incident took
        place at 13th and Decatur St....near Invesco Field.  The
        floodwaters inundated the bike trail adjacent to the creek.
        A woman with her child sought refuge under a bridge and
        became trapped by the high water.  The woman slipped and
        the stroller containing the child was swept into the swift
        current.  The child drowned.  Rainfall totaled 0.42 inches
        at Denver International Airport.  Elsewhere...golfball hail
        was reported near Hudson.  Hail...up to one inch in
        diameter...was observed in Boulder and Lyons.
        Thunderstorm wind gusts estimated to 70 mph were reported
        near Buckley Air Force Base...with a peak wind gust to 37
        mph observed at Denver International Airport.  A small
        tornado touched down near Ft. Lupton but did no damage.
14-15 In 1977...the 14th to the 15th...high winds up to 100 mph
        felled hundreds of trees in Gilpin County and caused
        extensive damage to telephone and power lines.  Lumber
        and steel tanks were blown around in Boulder Canyon.  West
        winds gusted to 46 mph at Stapleton International Airport
        on the 15th.
14-18 In 1996...from the 14th to the 18th...a period of unusually
        warm weather resulted in 4 record maximum temperatures in
        5 days.  The record high temperatures were 87 degrees on
        the 14th...89 degrees on the 15th...and 93 degrees on both
        the 16th and 18th.  The temperature climbed to only 81
        degrees on the 17th which was not a record.
15    In 1894...southwest winds were sustained to 38 mph with gusts
        to 50 mph.
      In 1910...an apparent cold front produced sustained northeast
        winds to 48 mph.
      In 1986...a thunderstorm dumped an inch of rain in an hour
        over the eastern part of Aurora.  Total rainfall from the
        storm was 1.62 inches.
      In 1989...a 47 year old man...a Lakewood police officer...was
        struck and injured by lightning.  Small hail piled up 3
        to 4 inches deep near Golden.  There was reported street
        flooding from heavy thunderstorm rains over western metro
        Denver.  Rainfall totaled 0.76 inch at Stapleton
        International Airport.
      In 1990...a thunderstorm produced a wind gust to 69 mph at
        Jefferson County Airport in Broomfield.  Thunderstorm winds
        gusting to 49 mph at Stapleton International Airport
        produced some blowing dust.
      In 1991...a funnel cloud was sighted near Morrison.  Later...
        hail up to 2 inches deep covered U.S. Highway 285 at South
        Turkey Creek Road in west metro Denver.  Baseball size hail
        was reported on the east side of Littleton.  Dime size hail
        was reported in Boulder.
      In 1993...lightning started a fire which damaged a home in
        Boulder.  No one was injured.
      In 1997...a wind gust to 58 mph was recorded at the site
        of the former Stapleton International Airport.  A street
        sign was blown down at the Havana Street exit along I-70.
      In 1999...lightning ignited a small fire in a 3-story
        structure in Sunshine Canyon above Boulder.  The fire
        was quickly extinguished and caused only minor damage.
      In 2003...thunderstorms produced very heavy rainfall and
        localized flash flooding in the foothills of central
        Boulder County.  Rainfall ranged from 1.5 to 2.5 inches
        in less than 2 hours.  Water ranging in depth from 6 to 9
        inches covered State Highway 119 in Boulder Canyon.  Dirt
        and rocks also washed over the roadway.  Some basements
        were flooded in the Sugarloaf area.  Rockslides were also
        reported at Boulder Falls...Lefthand Canyon...and Fourmile
        Canyon.
      In 2015...Severe thunderstorms produced hail...from nickel to
        half dollar size...across parts of Adams...Arapahoe...Douglas
        and Weld Counties. Two tornadoes touched down briefly in
        Adams County; one tornado...rated an EF1...destroyed a storage
        shed north of Strasburg.
15-16 In 1957...from the 15th to the 16th...heavy snowfall totaled
        8.8 inches at Stapleton Airport. The greatest amount on the
        ground was 3 inches.
      In 1986...from the 15th to the 16th...a spring storm dumped 1
        to 2 inches of rain over metro Denver...but 2.71 inches fell
        at Buckley Field in Aurora.  Rainfall only totaled 0.84
        inch at Stapleton International Airport.  Snow fell in the
        foothills with 7 inches recorded in Coal Creek Canyon
        southwest of Boulder.
16    In 1875...a heavy hail storm turned into heavy rain during
        the afternoon.  Rainfall totaled 0.86 inch in just 37
        minutes...while the temperature dropped 22 degrees in
        22 minutes.  Precipitation totaled 0.90 inch.
      In 1894...west winds were sustained to 48 mph with gusts
        to 56 mph.
      In 1949...a tornado was observed for 16 minutes...20 miles to
        the southeast of Stapleton Airport.  The tornado moved 5
        miles to the northeast before dissipating.  No damage was
        reported.
      In 1963...intense lightning started several forest fires in
        the foothills southwest of Denver near Deckers and
        Cheeseman Lake.  Little precipitation fell from the storms
        to alleviate the unusual dry conditions so early in the
        season.
      In 1978...thunderstorm winds caused damage in southeast
        Aurora.  Winds of 60 to 80 mph blew down numerous fences and
        damaged several homes under construction.  High winds tore
        docks loose at Cherry Creek Reservoir...sinking 3 or 4 boats
        and damaging about 15 others.  At Stapleton International
        Airport where winds gusted to 60 mph...a 727 jet suffered
        15 hundred dollars damage when wind toppled a runway light
        onto it.  The public reported an unconfirmed tornado 7 miles
        south-southwest of Stapleton International Airport.
      In 1990...a line of thunderstorms moving across metro Denver
        uprooted a large ash tree...which fell and blocked the
        outside doors to a Denver elementary school...briefly
        trapping the students inside.  Thunderstorm wind gusts to
        69 mph were reported at Jefferson County Airport.
        Northwest winds gusted to 44 mph at Stapleton International
        Airport.
      In 1991...two tornadoes touched down briefly in Castle Rock...
        but no injuries or damage were recorded.  Heavy
        thunderstorm rains of 0.50 to 1.10 inches in a couple of
        hours caused Lena Gulch near Golden to flood.  No damage
        was reported.
      In 1996...dry microburst winds of unknown strength overturned
        a trailer and damaged storage sheds in Strasburg east of
        Denver.
16-17 In 1981...from the 16th to the 17th...a heavy rain storm dumped
        1 to 2 1/2 inches of rain across metro Denver.  Rainfall
        totaled 1.27 inches at Stapleton International Airport where
        north winds gusted to 38 mph on 17th.
      In 1983...from the 16th to the 17th...a very strong late spring
        storm dumped heavy snow over the Front Range.  Strong winds
        with the storm produced blizzard conditions at times.
        Sustained winds were 20 to 40 mph with a peak gust to 55 mph
        at Stapleton International Airport.  The foothills received
        1 to 2 feet of snow with 4 to 12 inches along the foothills.
        Howling winds whipped the snow into drifts several feet
        deep...closing schools and highways.  Stapleton International
        Airport was forced to reduce flight operations...closing 2 of
        4 runways and stranding hundreds of travelers.  Most of the
        damage and inconvenience caused by the storm was in power
        outages...which occurred when wind and heavy wet snow caused
        hundreds of power poles to snap and topple.  About 20 square
        miles of Denver were blacked out.  Precipitation from the
        storm totaled 1 to 3 inches.  At Stapleton International
        Airport...snowfall totaled 7.1 inches with a maximum snow
        depth on the ground of only 2 inches due to melting.  The
        high temperature of 40 degrees on the 17th was a record low
        maximum for the date.  Due to the heavy moisture content
        of the storm...widespread street flooding occurred on the
        18th when much of the snow melted under the warm May sun
        and temperatures climbed to a high of 57 degrees.
      In 1995...from the 16th to the 17th...significant moisture and
        upslope flow caused flooding across metro Denver.  Moderate
        to heavy rains...which began on the evening of the 16th...
        developed in the foothills and spread eastward over metro
        Denver throughout the night.  The heavy rains brought many
        creeks and small streams to bankfull or slightly over.
        Locations along the foothills received between 3 and 4
        inches of rainfall from the storm.  Boulder received 3.60
        inches of rainfall for the 24-hour period...causing minor
        street flooding near small streams.  To the northwest of
        Boulder...a bridge which crossed Fourmile Creek was washed
        out.  Numerous rock and mudslides occurred in foothills
        canyons...closing portions of U.S. Highways 6 and 40 and
        State Highway 119 for a few hours at a time.  Rocks were
        piled 6 feet deep on a stretch of State Highway 119 along
        with boulders as large as cars on U.S. Highway 6.  A
        parking lot near a creek in Golden caved in leaving a
        hole the size of an 18-wheeler.  Rushing water washed out
        a 50-foot stretch of a road in Westminster.  Rainfall
        totaled 1.75 inches at Denver International Airport...but
        only 1.42 inches at the site of the former Stapleton
        International Airport.
17    In 1903...southwest winds were sustained to 42 mph with gusts
        to 45 mph from an apparent microburst which produced only
        a trace of rain.
      In 1960...hail to 3/4 inch diameter was measured in Thornton.
        Golf ball size hail fell in Arvada.
      In 1972...microburst winds gusted to 51 mph at Stapleton
        International Airport.
      In 1975...hail 1/2 to 3/4 inch in diameter fell over western
        metro Denver.
      In 1978...a small tornado touched down in south Aurora
        damaging 40 homes...6 to a considerable extent.  One garage
        was demolished and blown across the street.  Parts of roofs
        were completely blown away.  Several 2x4-inch boards were
        blown into the sides of houses.  Another small tornado in
        Parker damaged two airplanes.  Other funnel clouds were
        sighted over Northglenn and near Golden.
      In 1985...a thunderstorm produced a total of 1.50 inches of
        rain in Brighton where 0.72 inches fell in 40 minutes.
        Small hail covered the ground...and there was some street
        and basement flooding.
      In 1987...small hail piled up 4 inches deep in southwest
        Aurora.  There was also widespread street flooding and a
        few power outages.  Hail as large as 3/4 inch in diameter
        fell at Castle Rock.
      In 2000...high winds occurred along and east of the Front Range
        foothills...as a deep surface low pressure center formed over
        the northeast plains of Colorado.  An amusement park in
        north Boulder received about 25 thousand dollars in property
        damage.  Peak wind reports included:  88 mph at the National
        Wind Technology Center...84 mph in Boulder...and 80 mph at the
        National Center for Atmospheric Research Mesa Laboratory.
        A powder keg of severe weather...including tornadoes and
        thunderstorms producing large hail...damaging winds and
        heavy rain...occurred over the plains to the northeast of
        Denver.  The only severe weather reported across metro
        Denver was 1 inch diameter hail in Littleton.
17-19 In 2017...a strong spring storm dropped across the Great Basin...
        and then moved eastward across Colorado. Isolated but strong
        thunderstorms preceded the system on the 17th with hail up
        to nickel size near Boulder Airport and Brighton. Significant
        snow fell across the Front Range mountains and foothills over
        the next couple of days. Along the Interstate 25 Corridor...
        rain turned to snow on the morning of the 18th...heaviest from
        around Broomfield northward. The heavy wet snow snapped the
        limbs of fully leaved trees and caused scattered power
        outages. A barns collapsed in northeast Loveland. Fifty-five
        head of cattle were inside the collapsed barn; three were
        injured and later euthanized. Numerous branches and trees
        snapped in the foothills. Elsewhere...several scattered
        smaller power outages were reported. Three to nearly five
        inches of liquid precipitation occurred...as rain or a mix of
        rain and snow...fell around Greeley. Storm totals in the Front
        Range mountains and foothills included: 42.0 inches near
        Allenspark...41.5 inches near Ward...36 inches at Estes Park...
        32 inches near Pinecliffe...30.5 inches northwest of Golden...
        30 inches near Nederland...26 inches near Breckenridge...25
        inches near Aspen Springs and Bear Lake State Park...14
        inches at Aspen Springs...with 9.5 inches near Evergreen.
        On the west side of the Interstate 25 Corridor...storm
        totals included: 10 inches near Superior and Louisville...6
        to 8 inches in and around Fort Collins...6 inches in Lafayette...
        5 inches in Broomfield and Loveland...and 4 inches near Niwot.
18    In 1864...heavy rains combined with melting snow to cause much
        flooding on North Clear Creek in Blackhawk.  Many bridges on
        the road to Denver were washed away by the high water on
        Clear Creek.
      In 1893...northwest winds were sustained to 56 mph with an
        extreme velocity to 60 mph.
      In 1960...large hail to 1 inch in diameter damaged roofs and
        cars in metro Denver.  Heavy snow and rain in the foothills
        caused rock and landslides...which blocked some highways.
        There was widespread minor damage from lightning.
        Hail as large as 1 1/8 inch in diameter was measured at
        Stapleton Airport where winds gusted to 44 mph.
      In 1975...a tornado touched down briefly just south of Buckley
        Field in Aurora.  A few minutes later the same tornado
        touched down in open country 8 miles northeast of
        Stapleton International Airport.  No damage was reported.
      In 1985...3/4 inch hail fell just southeast of Aurora.
      In 1988...lightning started a fire at a home in the foothills
        west of Boulder...causing 50 thousand dollars in damage.
      In 1995...strong thunderstorms rumbled across metro Denver
        dropping mainly pea to marble size hail.  However...hail
        stones as large as 1 1/4 inches in diameter fell in Wheat
        Ridge and downtown Denver.  Hail piled up to 2 inches deep
        in Wheat Ridge and northwest Denver.
      In 1996...the Buffalo Creek wildfire started and spread
        rapidly on strong southwest winds at 20 to 30 mph.  Dry
        weather conditions contributed to the spread of the fire...
        which burned nearly 12 thousand acres and destroyed 12
        structures including some houses.
      In 2001...a 19-year-old man was struck and killed by lightning
        as he was walking along the shoulder of U.S. Highway 36 in
        Westminster.
      In 2003...hail to 3/4 inch in diameter was measured at Denver
        International Airport.
      In 2010...a small tornado touched down near Firestone but did
        no damage.
18-19 In 2011...from the 18th to the 19th...a severe thunderstorm in
        central Adams County produced large hail and heavy rainfall
        on the 18th. Large hail from 1 inch to 1 3/4 inches in
        diameter...was reported in Commerce City...near Federal
        Heights...Northglenn...and 2 miles south of Thornton.  In
        Commerce City...the storm uprooted trees and knocked out
        power lines. A carport was lifted off the ground and
        struck the power lines overhead. Heavy rain...from 1.0 to
        1.5 inches fell in less than 2 hours in Commerce City and
        near Brighton.  The combination of hail and strong winds
        broke windows in Northglenn.  In the foothills...moderate to
        heavy snow showers developed overnight. Storm totals
        included: 10.5 inches at Gold Hill...9.5 inches...3 miles
        west of Jamestown; 9 inches at Lake Eldora; with 6 inches...
        11 miles southwest of Gilpin and 4 miles east-northeast of
        Nederland. At Denver International Airport...total rainfall
        over the 2-day period totaled 1.71 inches.  In addition...a
        peak wind gust to 37 mph was recorded on the 18th.
18-20 In 1915...from the 18th to the 20th...3.9 inches of snow fell
        in the city.  The estimated amount of snow that melted as
        it fell was 6.2 inches which would have totaled an
        estimated 10.1 inches of snowfall. Precipitation totaled
        1.03 inches.  North winds were sustained to 32 mph on the
        18th.  Low temperatures dipped to 25 degrees on both the
        18th and 20th...establishing record minimums for both dates.
      In 1988...from the 18th to the 20th...a prolonged heavy
        rainfall drenched metro Denver.  The event began when heavy
        thunderstorms on the 18th caused some street flooding and
        power outages...followed by steady rain on the 19th and 20th.
        Rain amounts across metro Denver totaled 3 to 4 inches.
        Rainfall totaled 3.71 inches at Stapleton International
        Airport where north winds gusted to 39 mph on the 20th.
        Four to eight inches of snow fell in the foothills above 7
        thousand feet.
19    In 1927...southeast winds were sustained to 40 mph with gusts
        to 44 mph.
      In 1956...a thunderstorm wind gust to 54 mph was recorded at
        Stapleton International Airport.
      In 1969...hail stones to 1 inch in diameter were measured in
        Arvada and Aurora.  Some minor damage was reported.
        Pea to marble size hail fell in Westminster.
      In 1972...a tornado was reported by aircraft about 5 to 10
        miles east of Parker.
      In 1988...lightning started a fire at a house in the Denver
        suburb of Greenwood Village...causing 2 thousand dollars in
        damage.
      In 1991...strong thunderstorms over east metro Denver produced
        wind gusts of 56 to 60 mph.  The strong winds downed power
        lines...trees...and fences at some locations in Aurora.
        Thunderstorm outflow winds gusted to 60 mph at Stapleton
        International Airport.
      In 1994...severe thunderstorms rumbled across metro Denver.
        The storms produced wind gusts averaging 65 mph and hail up
        to dime size.  Wind gusts to 77 mph were recorded in
        Brighton.  Numerous trees and power poles were downed by
        the winds.  One power pole fell onto spectators at a high
        school graduation ceremony in Commerce City...injuring 6
        people.  In Fort Lupton...trees fell onto 2 parked cars...
        knocking out the windshields.  Hail to 3/4 inch in diameter
        was reported in Littleton.  A thunderstorm wind gust to 52
        mph was recorded at Stapleton International Airport.
      In 1995...a slow moving tornado...which was mainly discernible
        by its dust and debris cloud...was spotted 2 miles northeast
        of Denver International Airport or about 10 miles
        northwest of Bennett.  No damage was reported.
      In 2007...lightning struck a 33-ft statue of Jesus at Mother
        Cabrini Shrine...in the foothills west of Golden.  The blast
        broke off one of the statue`s arms and a hand...and also
        damaged a foot.  It cost an estimated $200000 to repair.
      In 2009...lightning struck the roof of a residence in Highlands
        Ranch.  The home was not a total loss...but the fire caused
        extensive damage.
      In 2010...a thunderstorm produced hail up to 7/8 inch in
        diameter in Thornton.
19-20 In 1864...from the 19th to the 20th...a devastating major flash
        flood occurred on the normally dry and sandy Cherry Creek
        in Denver.  The flood was caused by heavy thunderstorm
        rainfall and hail over the Palmer Ridge to the south of the
        city in both the Cherry Creek and Plum Creek basins.
        Nineteen deaths occurred along the South Platte River and
        Cherry Creek in Denver.  The torrent swept cattle and sheep
        along with large trees and houses before it washing out
        several bridges...and moving large structures from their
        foundations.  All city records were destroyed when City Hall
        washed away.  The Rocky Mountain News building...built on
        stilts in the middle of the creek...was totally destroyed
        by the raging waters...which were as deep as 5 feet on the
        morning of the 20th.  Once the flood waters receded...much
        sand and gravel was left behind.  Property damage from the
        flood was estimated at nearly one million dollars.  This
        was the first major flood of record in the city.

$$



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