Colorado, 2001

Hail and Damaging Wind in Colorado, July 23, 2001

July 23, 2001 · NWS BOU · 8 events in 4 counties and zones

7 hail, 1 thunderstorm wind, as filed by the National Weather Service.

Where it happened

Every event with a place to put it. Tap one for its entry below.

  • Tornadoes
  • Tropical storms and surge
  • Floods
  • Wind
  • Hail
  • Winter weather
  • Heat and drought
  • Cold
  • Fire, smoke and dust
  • Marine and coastal
  • Other

Open the live radar over this ground

The toll

Deaths
0
Injuries
0
Property damage
$606,000
Crop damage
$6,000
Events
8

Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.

What forecasters said that day

The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Denver/Boulder, CO wrote its last area forecast discussion before the first event at Jul 23, 1:15 PM MST, 1 hour 25 minutes earlier.

Area forecast discussion, Jul 23, 1:15 PM MST, 1 hour 25 minutes before
NORTHEAST AND NORTH CENTRAL COLORADO AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER COLORADO
215 PM MDT MON JUL 23 2001

SHORT TERM: THE 2ND SURGE THAT CAME IN THIS MORNING HAS BROUGHT VERY
HI DEWPOINTS INTO THE FTHLS ON GUD E TO NE FLOW.  CONVECTION HAS
BEEN UNDERWAY ALL MORNING ON THE PLAINS...PROBABLY AIDED BY THE
SURGE AND SOME UPR LVL FORCING WHOSE ORIGIN IS BIT UNCERTAIN...WTR
VPR IMAGERY INDC SOME W PROPAGATING GRAVITY WAVE ACTIVITY THAT
REACHED CWA THIS MRNG AS WELL.  AT ANY RATE PLENTY WET...AND HAVE
UPR LVL FORCING THAT WAS NOTED YSTDY OVER OLD MEX AND NOW APCHG THE
4CORNERS STILL TO MOVE ACRS AREA THIS EVNG/TONIGHT.  HVY RAINS WILL
CONT TO BE THE MAIN PROB AS LACK OF ANY CAP MAY PREVENT SUFFICIENT
CAPE FROM DVLPG FOR ORGANIZED SVR STORMS.  LATEST MM5HOT RUN HAS TWO
ROUNDS OF HVY RAIN PRODUCERS WITH ONE THIS AFTN THEN AN ORGNIZED
SYSTEM OVERNIGHT THAT DOESN'T END TIL 12Z OR SO...LOTS OF VERY HI
POPS IN STORE FOR TNGT.

LONGER TERM: A SECOND SURGE OF UPSLOPE IS STILL HEADING TOWARDS THE
AREA FOR TUE WITH THE SFC HI MOVG S INTO ND LATER TDAY.  LIKELY TO
BE LOTS OF LOW LVL CLDNS ARND TUE MRNG AFTER ACTIVE NIGHT OF STORMS
WCH CUD SLOW DOWN STORM DVLPMNT ON THE PLAINS TILL LATER IN THE AFTN
ASSUMING THERE IS NO OTHER TRIGGER ARND...THO THE MTNS SHD CONVECT
IN THE USUAL FASHION.  LUKG AT D3D LOOP APPEARS THERE WILL BE SOME
FORCING FOR LATER TUE ARISING FROM A WAVE CURRENTLY OVER BAJA.  FOR
WED PLENTY OF MSTR STILL IN PLACE AT LOW LVLS AS THE SFC HI WORKS E
AND THE FLOW BCMS MORE SLY ON THE PLAINS...SO MAYBE A DENVER CYCLONE
TO GO ALONG WITH THE MIX.  SUPPORT ALOFT BY WED WILL PROB COME AS
THE TROF NOW OVER CA/NV WORKS ITS WAY EAST WITH ITS ASSOC JET STREAM
GETTING CLOSER TO THE AREA...WCH MAY WELL LOWER TEMPS ALOFT A BIT
FOR PERHAPS THE BEST LAPSE RATE DURING THE PERIOD.  THE ETA EVEN
INDC POSSIBLE GOOD UPR LEVEL JET CONFIGURATION FOR EVEN MORE FORCING
BY WED AFTN BUT EVEN WITHOUT ANY OF THIS JUST THE LOW LVL MSTR WILL
BE PLENTY TO WORK WITH.  MOIST ALSO OVER THE MTNS WITH THE MONSOON
PLUME ON THE WTR VPR IMAGERY NOW EXTENDING WELL WEST INTO UT.
QUESTION THEN IS WHEN WILL CONDITIONS SETTLE DOWN...YESTERDAY IT
LOOKED LIKE THU WUD DRY OUT AS THE TROF TO OUR W...IN A WEAKENED
STATE...MOVES THRU LATE WED.  NOW THINGS LUK A LITTLE SLOWER SO THAT
THU CUD STAY RATHER MOIST AS WELL UNTIL WHAT IS LEFT OF THE TROF
FINALLY MOVES ACROSS.

FOR FARTHER AHEAD LAST NGTS MRF TAKES THE NEXT SYSTEM INTO THE PAC
NW AND RIDES IT WAY OVER THE RIDGE RATHER THAN STRAIGHT ACRS NRN
CONUS...SO YSTDY THE MRF INDC A GUD FROPA BY LATER SUN/MON WHEREAS
TDY AT BEST A WEAK ONE BY MON.  LATEST AVN EXTENSION SUGGESTS THERE
WILL BE MORE ENERGY DIVING INTO THE PAC NW...WCH THE UKMET HAS BEEN
SHOWING AS WELL...SO THIS WUD TEND TO KEEP MORE OF A TROF BACK THERE
VS LIFTING E...WCH SHD SLOW THINGS FURTHER.  SO FOR NOW WILL KEEP
FRI TO MON PERIOD TOGETHER AS WARMER AND NOT AS MOIST...STILL ENUF
MONSOON MSTR ARND FOR SLGT CHC TSTM MENTION.   SZOKE

.DEN...NONE.

In the hours before

Special weather statement, Jul 23, 9:15 AM MST, 5 hours 25 minutes before
COZ030>051-232000-

SIGNIFICANT WEATHER OUTLOOK FOR NORTHEAST AND NORTH CENTRAL COLORADO
NATIONAL WEATHER SERVICE DENVER CO
1015 AM MDT MON JUL 23 2001

THIS OUTLOOK PERTAINS TO THE FOLLOWING COLORADO COUNTIES

ADAMS     ARAPAHOE     BOULDER   CLEAR CREEK   DENVER       DOUGLAS
ELBERT    GILPIN       GRAND     JACKSON       JEFFERSON    LARIMER
LINCOLN   LOGAN        MORGAN    PARK          PHILLIPS     SEDGWICK
SUMMIT    WASHINGTON   WELD

SYNOPSIS:  MOISTURE HAS INCREASED OVER THE PLAINS BEHIND A SURFACE
FRONT.  THE AIRMASS IS UNSTABLE THIS MORNING...AND ISOLATED SHOWERS
AND THUNDERSTORMS WILL CONTINUE ACROSS THE PLAINS BEFORE EXITING THE
STATE AROUND NOON.

THE INSTABILITY WILL INCREASE DURING THE AFTERNOON AND AN UPPER
LEVEL DISTURBANCE IS EXPECTED TO MOVE ACROSS THE AREA.  SHOWERS AND
THUNDERSTORMS WILL DEVELOP OVER THE MOUNTAINS AND FOOTHILLS...MOVING
ONTO THE PLAINS DURING THE AFTERNOON AND REACHING THE NORTHEAST
BORDER DURING THE EVENING.  SOME STORMS COULD BECOME SEVERE EAST OF
A GREELEY TO LIMON LINE WHERE A FAVORABLE WIND PROFILE EXISTS.  HAIL
UP TO AN INCH IN DIAMETER AND WIND GUSTS TO WILL BE THE PRIMARY
THREAT.  DUE TO THE INCREASE OF MOISTURE IN THE ATMOSPHERE...HEAVY
RAIN IS ALSO POSSIBLE.

SPOTTER ACTIVATION MAY BE REQUIRED FOR THE EASTERN PLAINS THIS
AFTERNOON.

LESZCYNSKI
Special weather statement, Jul 23, 12:55 PM MST, 1 hour 45 minutes before
COZ030>051-232200-

SIGNIFICANT WEATHER OUTLOOK FOR NORTHEAST AND NORTH CENTRAL COLORADO
NATIONAL WEATHER SERVICE DENVER CO
155 PM MDT MON JUL 23 2001

THIS OUTLOOK PERTAINS TO THE FOLLOWING COLORADO COUNTIES

ADAMS     ARAPAHOE     BOULDER   CLEAR CREEK   DENVER       DOUGLAS
ELBERT    GILPIN       GRAND     JACKSON       JEFFERSON    LARIMER
LINCOLN   LOGAN        MORGAN    PARK          PHILLIPS     SEDGWICK
SUMMIT    WASHINGTON   WELD

SYNOPSIS:  SCATTERED SHOWERS AND THUNDERSTORMS WILL CONTINUE OVER
THE AREA DURING THE AFTERNOON AND EARLY EVENING HOURS.  BRIEF HEAVY
RAIN AND WIND GUSTS TO 40 MPH CAN BE EXPECTED ALONG WITH SMALL HAIL.
THE HEAVY RAIN COULD CAUSE LOCALIZED FLOODING ACROSS DOUGLAS...
SOUTHERN JEFFERSON AND WESTERN ELBERT COUNTIES.

AN UPPER LEVEL WEATHER DISTURBANCE IS EXPECTED TO MOVE ACROSS THE
AREA THIS AFTERNOON WITH THE ATMOSPHERE BECOMING INCREASING UNSTABLE.
SOME STORMS COULD BECOME SEVERE EAST OF A GREELEY TO LIMON LINE
WHERE THERE IS A FAVORABLE WIND PROFILE.  HAIL UP TO AN INCH IN
DIAMETER AND WIND GUSTS TO 65 MPH ARE POSSIBLE.

SPOTTER ACTIVATION MAY STILL BE REQUIRED FOR THE EASTERN PLAINS
AFTER 4PM.

$i$
LESZCYNSKI

The radar

The Goodland radar (KGLD), 154 km away, was scanning. The volume nearest the first event began at 21:39 UTC.

Open the radar archive at this moment

Event by event

7 hail, 1 thunderstorm wind. Local standard time, as filed.

Hail, Phillips

When
July 23, 2:40 PM MST to 3:10 PM MST
Where
Phillips County, 4 mi W of Amherst
Measured
1.75 in hail
Reported by
TRAINED SPOTTER
Coordinates
40.683, -102.250

Hail, Phillips

When
July 23, 2:45 PM MST
Where
Phillips County, 5 mi NW of Amherst
Measured
2.25 in hail
Reported by
TRAINED SPOTTER
Coordinates
40.733, -102.233

Thunderstorm Wind, Elbert

When
July 23, 2:55 PM MST
Where
Elbert County, 9 mi S of Simla
Measured
70 kt (81 mph)
Reported by
TRAINED SPOTTER
Coordinates
39.033, -104.033

Intense thunderstorm winds blew the roof off a shed.

Hail, Arapahoe

When
July 23, 3:00 PM MST
Where
Arapahoe County, Littleton
Measured
1.25 in hail
Reported by
TRAINED SPOTTER
Coordinates
39.617, -105.000

Hail, Arapahoe

When
July 23, 3:05 PM MST
Where
Arapahoe County, 1 mi S of Sheridan
Measured
1.25 in hail
Reported by
TRAINED SPOTTER
Coordinates
39.650, -105.017

Hail, Sedgwick

When
July 23, 3:14 PM MST
Where
Sedgwick County, 15 mi S of Julesburg
Measured
1.75 in hail
Reported by
TRAINED SPOTTER
Coordinates
40.767, -102.267

Hail, Arapahoe

When
July 23, 3:15 PM MST
Where
Arapahoe County, Littleton
Measured
1.5 in hail
Property damage
$606,000
Crop damage
$6,000
Reported by
TRAINED SPOTTER
Coordinates
39.617, -105.000

The city of Littleton suffered $612,000 in damage to vehicles, roofs, buildings, landscaping and computers. Almost every vehicle owned by visitors and employees in the Littleton Center parking lot sustained damage.

Hail, Phillips

When
July 23, 3:16 PM MST
Where
Phillips County, Amherst
Measured
1.75 in hail
Reported by
TRAINED SPOTTER
Coordinates
40.683, -102.167

What these are

Hail
Hail three-quarters of an inch or larger, or smaller hail that caused damage, filed with the largest stone measured.
Thunderstorm Wind
Winds from a thunderstorm of 50 knots (58 mph) or more, or lower winds that caused damage or casualties. Measured gusts are marked MG, estimated EG.

After NWS Directive 10-1605, the rules offices file Storm Data by.

The same day elsewhere

More

Every storm in Colorado in 2001Every state in 2001This day in weather historyWarnings in Colorado, July 2001

Sources

NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 5267377, 5267381, 5267374, 5267375, 5267376, 5267378, 5267379, 5267380.