Flash Flooding and Hail in Colorado, July 8, 2001

Name: Flash Flooding and Hail in Colorado, July 8, 2001
Start: 2001-07-08T00:29
End: 2001-07-08T18:45
Location: Colorado

July 8, 2001 · NWS BOU · 14 events in 4 counties and zones

6 hail, 5 thunderstorm wind, 2 flash flood, 1 lightning, as filed by the National Weather Service.

Where it happened

Every event with a place to put it; 3 filed by county or forecast zone are drawn at its center, in a lighter ring. 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: 4
Property damage: None recorded
Crop damage: None recorded
Events: 14

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 7, 2:30 PM MST, 9 hours 59 minutes earlier.

Area forecast discussion, Jul 7, 2:30 PM MST, 9 hours 59 minutes before

NORTHEAST AND NORTH CENTRAL COLORADO AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER COLORADO
330 PM MDT SAT JUL 7 2001

NEXT COUPLE OF DAYS LOOK INCREASINGLY WET FOR NERN CO AS STUBBORN
UPR LVL HIGH SPINNING OVR OKLAHOMA WOBBLES A BIT EASTWARD...OPENING
THE DOOR TO MONSOON FLOW.  H20 VAPOR IMAGERY SHOWS AMPLE MID/UPR LVL
MOISTURE STREAMING NWRD UP INTO UT AND WRN CO ATTM.  EMBEDDED WITHIN
THIS FLOW IS A FAIRLY STG MID-LVL VORT MAX NOW OVR NWRN CORNER OF
STATE.  A SECOND VORT MAX CAN ALSO BE SEEN CREEPING N/NWWRD OVR THE
NRN TX/OK PANHANDLES.  IT/S THE NRN DISTURBANCE THAT WILL PROVIDE
THE ENERGY FOR EVENING T-STORMS OVR AND ALONG THE FRONT RANGE.  IN
PAST HR T-STORM PASSING OVR FRASER PRODUCED MARBLE SIZE HAIL.  RADAR
HAS ALSO INDICATING FAIRY HVY RAINFALL /UP TO 1.5 INCH PER HR/ WITH
STORM CROSSING LARIMER CTY.  MODEL SOUNDINGS SHOW UPWARDS OF 1.2
INCHES OF PRECIPITABLE WATER THIS EVENING AROUND DEN...BOU...GLY AND
FCL...AND SFC DEWPTS IN THE MID 50S TO LOWER 60S.  USING LATEST ACRS
SOUNDINGS...CAPES PROGD TO BE IN THE 1200 TO 2100 J/KG RNG IN PARTS
OF THE URBAN CORRIDOR AND ON THE ADJACENT PLAINS.  FURTHERMORE WILL
HV TO WATCH FOR CONVECTIVE INITIATION ALONG A SFC BNDRY SITTING NRLY
STNRY THE PAST SVRL HRS ROUGHLY FM CHATFIELD RESERVOIR/SW OF DEN/ TO
WIGGINS IN WRN MORGAN CTY.  COULD SEE A FEW HVY RAINERS CROP UP
ALONG THIS BNDRY WITH STORM MOTIONS EXPECTED TO BE QUITE WK.  STORMS
ROLLING OFF FRONT RANGE THE NRN HALF OF URBAN CORRIDOR AND NRN WELD
CTYS COULD PSBLY BECOME SVR WITH LARGE HAIL AND VRY STONG T-STORM
WINDS MAIN RISK.  WITH VORT MAX/SHRTWV OUT OF THE AREA BY
MIDNIGHT...SKIES SHOULD GO CLR/MOSTLY CLR ALL AREAS.

ON SUNDAY...CHANCES FOR MEASURABLE RAINFALL INCREASE PARTICULARLY BY
LATE INTHE DAY WITH PASSAGE OF YET ANOTHER STG VORT MAX/SHRT WV
EMBEDDED WITH A DEEP LAYER OF MONSOON MOISTURE.  PRECIPITABLE WATER
VALUES RISE AND DEWPTS E OF MTNS ALSO ON THE INCREASE WITH ARRIVAL
OF WHAT APRS TO BE A WEAK NLY SURGE DURING THE MRNG HRS.  CROSS
SECTIONS SHOW E-SELY FLOW DEEPENING DURING THE DAY WITH CAPES APCHG
TO 2500-3000 J/KG BY LATE AFTN UP ALONG THE FNT RNG FTHLS.  RIGHT
NOW CHANCES LOOK PRETTY GOOD FOR AREAS OF HVY RAINFALL IN AND NEAR
THE FTHLS BY LATE IN THE DAY.  WILL REALLY NEED TO KP AN EYE ON
THIS.  WITH INCREASE IN MOISTURE AND THE SHFT IN WINDS...TEMPS MAY
NOT RISE MUCH ABV 90 ON THE PLAINS.  HWVR AVN AND MRF TEMP GUIDANCE
LOOK TOO COOL...AS THEY HAVE FOR THE PAST SVRL WEEKS.

LOOKING AHEAD MONDAY THROUGH SATURDAY...CHANCES LOOK GOOD WE'LL HV
ANOTHER CHANCE FOR HVY LATE DAY RAINFALL MONDAY.  ALSO SEE DAYTIME
TEMPS ON THE PLAINS NOT GETTING OUT OF THE 80S.  THIS WOULD BREAK
THE LONG STRETCH OF 90 DEG WX WE/VE BEEN HAVING.  LATER IN THE
WEEK...MEDIUM RNG MODELS SHOW UPR RIDGE OVR THE LOWER GREAT PLAINS
CREEPING WESTWARD...CONSEQUENTLY SHIFTING THE DEEPEST MONSOON FLOW
AWAY FROM US.  STILL THERE SHOULD BE ENOUGH MOISTURE AROUND TO
PRODUCE THE TYPICAL ROUND OF AFTN AND EVE STORMS EACH DAY.  ALSO SEE
TEMPS RETURNING TO THE 90S ON THE PLAINS AFTER MONDAY/S BRIEF COOL
DOWN.    BAKER

.DfEN...NONE.

In the hours before

Local storm report, Jul 7, 10:13 PM MST, 2 hours 16 minutes before

LOCAL STORM REPORT
NATIONAL WEATHER SERVICE DENVER CO
1113 PM MDT SAT JUL 07 2001

...PRELIMINARY STORM REPORT FOR JULY 07 2001...

TIME(MDT)  .....CITY LOCATION.....STATE   ...EVENT/REMARKS...
           ....COUNTY LOCATION....

0740 PM    THORNTON                  CO   0.88 INCH HAIL
07/07/01   ADAMS

0900 PM    6 SE ERIE                 CO   1.75 INCH HAIL
07/07/01   WELD

Local storm report, Jul 8, 12:01 AM MST, 28 minutes before

LOCAL STORM REPORT
NATIONAL WEATHER SERVICE DENVER CO
0101 AM MDT SAT JUL 08 2001

...PRELIMINARY STORM REPORT FOR JULY 08 2001...

TIME(MDT)  .....CITY LOCATION.....STATE   ...EVENT/REMARKS...
           ....COUNTY LOCATION....

1252 AM    15 WNW STERLING           CO   0.75 INCH HAIL
07/08/01   LOGAN

Local storm report, Jul 8, 12:09 AM MST, 20 minutes before

LOCAL STORM REPORT
NATIONAL WEATHER SERVICE DENVER CO
0109 AM MDT SAT JUL 08 2001

...PRELIMINARY STORM REPORT FOR JULY 07 2001...

TIME(MDT)  .....CITY LOCATION.....STATE   ...EVENT/REMARKS...
           ....COUNTY LOCATION....

0740 PM    THORNTON                  CO   0.88 INCH HAIL
07/07/01   ADAMS

0900 PM    6 SE ERIE                 CO   1.75 INCH HAIL
07/07/01   WELD

1157 PM    6SW NEW RAYMER            CO   1.75 INCH HAIL
07/07/01   MORGAN

The radar

The Goodland radar (KGLD), 181 km away, was scanning. The volume nearest the first event began at 07:28 UTC.

Open the radar archive at this moment

Event by event

6 hail, 5 thunderstorm wind, 2 flash flood, 1 lightning. Local standard time, as filed.

Thunderstorm Wind, Sedgwick

When: July 8, 12:29 AM MST
Where: Sedgwick County, 5 mi S of Sedgwick
Measured: 52 kt (60 mph)
Reported by: TRAINED SPOTTER
Coordinates: 40.867, -102.517

Hail, Larimer

When: July 8, 11:42 AM MST
Where: Larimer County, Glen Haven
Measured: 0.75 in hail
Reported by: TRAINED SPOTTER
Coordinates: 40.450, -105.433

Hail, Denver

When: July 8, 3:23 PM MST
Where: Denver County, South Denver
Measured: 0.88 in hail
Reported by: TRAINED SPOTTER
Coordinates: 39.683, -104.967

Hail, Arapahoe

When: July 8, 3:41 PM MST
Where: Arapahoe County, Englewood
Measured: 1.25 in hail
Reported by: TRAINED SPOTTER
Coordinates: 39.650, -104.983

Hail, Arapahoe

When: July 8, 3:42 PM MST
Where: Arapahoe County, Littleton
Measured: 0.75 in hail
Reported by: TRAINED SPOTTER
Coordinates: 39.617, -105.000

Thunderstorm Wind, Arapahoe

When: July 8, 3:45 PM MST
Where: Arapahoe County, Englewood
Measured: 54 kt (62 mph)
Reported by: TRAINED SPOTTER
Coordinates: 39.650, -104.983

Hail, Denver

When: July 8, 3:48 PM MST
Where: Denver County, Denver
Measured: 1 in hail
Reported by: TRAINED SPOTTER
Coordinates: 39.733, -104.933

Thunderstorm Wind, Denver

When: July 8, 4:00 PM MST
Where: Denver County, South Denver
Measured: 50 kt (58 mph)
Injuries: 1 direct, 0 indirect
Reported by: NEWSPAPER
Coordinates: 39.683, -104.967

A wet microburst caused the roof of a hardware store in Tamarac Square to collapse. One employee received minor injures when she was struck in the head by falling debris. The combination of intense rain and wind downed trees and power lines. Electrical outages affected 35,000 homes and businesses. At least 50 trees in the city parks across South Denver were damaged.

Thunderstorm Wind, Arapahoe

When: July 8, 4:00 PM MST
Where: Arapahoe County, Aurora Cherry Creek
Measured: 50 kt (58 mph)
Injuries: 2 direct, 0 indirect
Reported by: NEWSPAPER
Coordinates: 39.633, -104.800

Two people received minor injuries when a wet microburst blew over several tents at the Cherry Creek Arts Festival.

Hail, Arapahoe

When: July 8, 4:07 PM MST
Where: Arapahoe County, Englewood
Measured: 1 in hail
Reported by: TRAINED SPOTTER
Coordinates: 39.650, -104.983

Thunderstorm Wind, Denver

When: July 8, 4:20 PM MST
Where: Denver County, Denver Intl Arpt
Measured: 55 kt (63 mph)
Reported by: TRAINED SPOTTER
Coordinates: 39.767, -104.883

Lightning, Denver

When: July 8, 4:30 PM MST
Where: Denver County, Denver
Injuries: 1 direct, 0 indirect
Reported by: NEWSPAPER
Coordinates: 39.762, -104.876 (the zone’s center; the record gives no point)

A man received minor injuries when lightning struck a nearby tree at the Wellshire Golf Course.

Flash Flood, Arapahoe

When: July 8, 5:21 PM MST to 6:45 PM MST
Where: Arapahoe County, Aurora Cherry Creek
Reported by: NEWSPAPER
Coordinates: 39.650, -104.339 (the zone’s center; the record gives no point)

Up to 4.5 inches of rain fell across portions of western Arapahoe County. The underpass of Interstate 25 and Parker Road was inundated with 5 feet of water. Several other streets and underpasses in Aurora were also closed due to the high water. Heavy rain caused extensive damage to several exhibits on display at the Cherry Creek Arts Festival.

Flash Flood, Denver

When: July 8, 5:25 PM MST to 5:45 PM MST
Where: Denver County, South Denver
Reported by: NEWSPAPER
Coordinates: 39.762, -104.876 (the zone’s center; the record gives no point)

Flash flooding occurred when heavy rainfall caused Toll Gate Creek to jump its banks. Several underpasses across South Denver had to be closed due to high water.

What these are

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.
Hail: Hail three-quarters of an inch or larger, or smaller hail that caused damage, filed with the largest stone measured.
Lightning: A lightning strike that killed, injured or caused damage.
Flash Flood: Flooding that begins within six hours of the rain that causes it, or of a dam or levee failure or ice jam release, often with deadly speed.

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

The same day elsewhere

Every storm in Colorado in 2001 Every state in 2001 This day in weather history Warnings 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: 5267134, 5267051, 5267052, 5267053, 5267054, 5267055, 5267056, 5267061, 5267135, 5267057, 5267058, 5267059, 5267060, 5267136.