Flash Flooding and Hail in Colorado, July 10, 2002

Name: Flash Flooding and Hail in Colorado, July 10, 2002
Start: 2002-07-10T13:00
End: 2002-07-10T19:08
Location: Colorado

July 10, 2002 · NWS BOU · 18 events in 9 counties and zones

16 hail, 2 flash flood, as filed by the National Weather Service.

Where it happened

Every event with a place to put it; 2 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: 0
Property damage: $10,000
Crop damage: None recorded
Events: 18

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 10, 1:37 AM MST, 11 hours 23 minutes earlier.

Area forecast discussion, Jul 10, 1:37 AM MST, 11 hours 23 minutes before

NORTHEAST AND NORTH CENTRAL COLORADO AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER COLORADO
240 AM MDT WED JUL 10 2002

SHORT TERM DISCUSSION: GOT A FEW STORMS TO FIRE ALONG CONVERGING
OUTFLOW BOUNDARIES OVERNIGHT...BUT THINGS HAVE NOW SETTLED DOWN.
SECONDARY SURGE MOVING THRU DEN ATTM WITH SOME INCREASE IN SURFACE
BASED MOISTURE. SURFACE HIGH ACROSS MONTANNA AND NRN WY WILL
CONTINUE TO SETTLE INTO THE REGION TODAY AND WILL KEEP A WEAK NE-E
LOW LVL FLOW FOR TODAY. AMS WILL BE CAPPED TODAY OVER THE PLAINS
WITH THETA-E RIDGE DISPLACED WESTWARD OVER THE MOUNTAINS/FOOTHILLS.
TEMPS WILL BE A LITTLE COOLER TODAY BEHIND FRONT AS 700MB TEMPS DOWN
TO AROUND +14C. WILL LOWER POPS SLIGHTLY OVER WESTERN PORTIONS OF
LOWER ELEVATIONS...WITH NO CHANCE OF STORMS OVER THE FAR EASTERN
PLAINS. ENTREKIN

THE LONG TERM DISCUSSION: STG H5 RDG WL RATTLE ARND THE UPR GRT
BASIN THE NXT SVRL DAYS.  A VERY STG...COLD (FOR THIS TIME OF YEAR)
S/W WL PLOW THRU THE UPR MIDWEST WED AND THURS AND IN THE WAKE OF
THIS SYS...STG CAA WL CONT OVR KS AND NEBR.  OVR OUR AREA...DP NLY
FLOW IS PROGGED TO CONT THRU THE DAY FRI.  00Z AVN KPS THE COOL...
STBL AIR ACRS THE PLAINS INTO FRI EVE...WHICH REPRESENTS A LTL
SLOWER SOLN THAN THE PAST FEW RUNS.  IN FACT...A REINFORCING SURGE
CAN BE INFERED ON SOME OF THE PLAN VIEWS ELY FRI MRNG. AVN MOS GNDC
HAS A HIGH OF 80 IN DENVER AS A RESULT.  BUT THE MODELS HAVE BEEN
CONSISTANTLY TOO COOL WITH TEMPS THE PAST SVRL DAYS.  A FEW DAYS
AGO...AVN WAS ADVERTIZING TEMPS IN THE LWR 80S ACRS THE ERN PLAINS
FOR TUES.  AKRON WAS 97 YESTERDAY...SO MDL PERFORMANCE WRT TEMPS
HASNT BEEN TOO STELLAR.  WL GO WITH UPR 80S-LWR 90S ACRS THE FNT
RANGE WITH SOME MID 80S FOR THE FAR NERN CORNER.  MSTR WL BE NRLY
GONE...PW/S OF UNDER A HALF INCH ALG WITH STBL AIR BLO H5 EQUATES
NICELY TO THE CURRENT DRY FCST SO NO CHGS TO POPS PLANNED.  WL INCRS
AFTN CLDS TO PTLY CLDY ACRS HIGH FRI COUNTRY THO.

SAT AND BYND...VRY LTL CHGS TO THE OVRALL SYNOPTIC PATTERN THRU THE
ENTIRE FCST PD.  A NRLY CONTINUOUS FEED OF MSTR FM THE EAST WL
STREAM INTO AZ/NEW MEXICO THE NEXT SVRL DAYS...BUT IT APPEARS THIS
CWFA WL RMN UNDER DRY N-NWLY FLOW ALF.  STILL NOT CRAZY ABT DRY FCST
OMTNS THRU THE ENTIRE EXTENDED PERIOD. EVEN THO MDLS ARE DRY...CLIMO
DOESNT SUPPORT 5 DRY DAYS IN A ROW IN THE HIGH COUNTRY THIS TIME OF
YEAR. WL LET LTR SHIFTS PONDER THIS AND WL JUST RAISE HIGH TEMPS
OMTNS IN UPCOMING ZFP...BUT OTWS LV FCST AS IS. 46

.DEN...NONE

In the hours before

Special weather statement, Jul 10, 10:03 AM MST, 2 hours 57 minutes before

COZ030>051-102000-

HAZARDOUS WEATHER OUTLOOK FOR NORTHEAST AND NORTH CENTRAL COLORADO
NATIONAL WEATHER SERVICE DENVER COLORADO
1103 AM MDT WED JUL 10 2002

THIS OUTLOOK PERTAINS TO THE FOLLOWING COLORADO COUNTIES

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

SYNOPSIS:  CURRENTLY...PLENTY OF LOW LEVEL MOISTURE IS COVERING THE
PLAINS AND FOOTHILLS OF THE FORECAST AREA.  LATER IN THE AFTERNOON
THE NORTHEAST CORNER OF COLORADO IS EXPECTED TO DRY OUT SOMEWHAT BUT
THE MOISTURE IS EXPECTED TO CONTINUE OVER THE FRONT RANGE FOOTHILLS
...ADJACENT PLAINS...AND PALMER RIDGE.  THE LOW LEVEL WINDS ARE
EXPECTED TO BE EASTERLY OR UPSLOPE...OVER THE PLAINS THIS AFTERNOON
AND THIS EVENING.  THE ATMOSPHERE OVER THE FORECAST AREA HAS SOME
STABLE LAYERS WITHIN IT AND EVEN WITH FAIRLY DECENT HEATING EXPECTED
ALONG WITH THE LOW LEVEL MOISTURE...ONLY ISOLATED SHOWERS AND
THUNDERSTORMS ARE FORECAST FOR MOST OF THE PLAINS.  THE
FOOTHILLS...PALMER RIDGE AND PARK COUNTY CAN EXPECTED SCATTERED
COVERAGE OF STORMS TO START DEVELOPING BEFORE THE NOON HOUR.  THE
ISOLATED STORMS ON THE PLAINS CAN BE EXPECTED AFTER 2:30 PM.  THE
FAR NORTHEAST CORNER OF THE START WILL HAVE NO SHOWERS OR
THUNDERSTORMS.

SPOTTER ACTIVATION IS NOT EXPECTED TODAY.

ON THURSDAY...THE FORECAST AREA WILL DRY OUT SOMEWHAT SO ONLY
ISOLATED SHOWERS AND THUNDERSTORMS CAN BE EXPECTED BY AFTERNOON OVER
THE MOUNTAINS AND FOOTHILLS.

RJK

The radar

The Denver radar (KFTG), 64 km away, was scanning. The volume nearest the first event began at 20:45 UTC.

Open the radar archive at this moment

Event by event

16 hail, 2 flash flood. Local standard time, as filed.

Flash Flood, Jefferson

When: July 10, 1:00 PM MST to 3:00 PM MST
Where: Jefferson County, South Portion
Property damage: $10,000
Reported by: LAW ENFORCEMENT
Coordinates: 39.586, -105.250 (the zone’s center; the record gives no point)

Runoff from heavy rainfall in the Hayman burn area flooded Lost Creek Ranch with up to 18 inches of water, just off of State Highway 126. Floodwaters ruined a very expensive rug in the lodge. Also, a driveway to another local residence was washed out. In Douglas County, runoff damaged some of the smaller access roads in the Turkey Creek Drainage.

Flash Flood, Douglas

When: July 10, 1:00 PM MST to 3:00 PM MST
Where: Douglas County, West Portion
Reported by: LAW ENFORCEMENT
Coordinates: 39.330, -104.930 (the zone’s center; the record gives no point)

Hail, Jefferson

When: July 10, 1:48 PM MST
Where: Jefferson County, 6 mi SW of Deckers
Measured: 0.75 in hail
Reported by: TRAINED SPOTTER
Coordinates: 39.183, -105.317

Hail, Douglas

When: July 10, 2:08 PM MST
Where: Douglas County, 3 mi S of Sedalia
Measured: 0.75 in hail
Reported by: TRAINED SPOTTER
Coordinates: 39.383, -104.967

Hail, Douglas

When: July 10, 2:37 PM MST
Where: Douglas County, 5 mi SSE of Parker
Measured: 1 in hail
Reported by: TRAINED SPOTTER
Coordinates: 39.450, -104.733

Hail, Douglas

When: July 10, 2:40 PM MST
Where: Douglas County, 6 mi SE of Parker
Measured: 3 in hail
Reported by: TRAINED SPOTTER
Coordinates: 39.450, -104.683

Hail, Arapahoe

When: July 10, 3:07 PM MST
Where: Arapahoe County, 1 mi N of (Apa)englwood Arapah
Measured: 2 in hail
Reported by: TRAINED SPOTTER
Coordinates: 39.583, -104.833

Hail, Arapahoe

When: July 10, 3:10 PM MST
Where: Arapahoe County, 1 mi NW of (Apa)englwood Arapah
Measured: 1.25 in hail
Reported by: TRAINED SPOTTER
Coordinates: 39.583, -104.850

Hail, Arapahoe

When: July 10, 3:15 PM MST
Where: Arapahoe County, 1 mi E of (Apa)englwood Arapah
Measured: 0.75 in hail
Reported by: TRAINED SPOTTER
Coordinates: 39.567, -104.817

Hail, Broomfield

When: July 10, 4:47 PM MST
Where: Broomfield County, Broomfield
Measured: 0.75 in hail
Reported by: TRAINED SPOTTER
Coordinates: 39.917, -105.067

Hail, Elbert

When: July 10, 4:49 PM MST
Where: Elbert County, 8 mi WSW of Agate
Measured: 0.75 in hail
Reported by: TRAINED SPOTTER
Coordinates: 39.417, -104.083

Hail, Adams

When: July 10, 5:02 PM MST
Where: Adams County, 8 mi SW of Henderson
Measured: 0.75 in hail
Reported by: TRAINED SPOTTER
Coordinates: 39.833, -104.967

Hail, Denver

When: July 10, 5:10 PM MST
Where: Denver County, Denver
Measured: 0.75 in hail
Reported by: TRAINED SPOTTER
Coordinates: 39.733, -104.933

Hail, Elbert

When: July 10, 5:16 PM MST
Where: Elbert County, 4 mi NE of Matheson
Measured: 1.25 in hail
Reported by: TRAINED SPOTTER
Coordinates: 39.200, -103.933

Hail, Arapahoe

When: July 10, 5:24 PM MST
Where: Arapahoe County, 2 mi E of Deer Trail
Measured: 0.75 in hail
Reported by: TRAINED SPOTTER
Coordinates: 39.617, -104.017

Hail, Adams

When: July 10, 5:27 PM MST
Where: Adams County, 4 mi SW of Brighton
Measured: 0.75 in hail
Reported by: TRAINED SPOTTER
Coordinates: 39.950, -104.867

Hail, Morgan

When: July 10, 6:34 PM MST
Where: Morgan County, 13 mi S of Wiggins
Measured: 1 in hail
Reported by: TRAINED SPOTTER
Coordinates: 40.050, -104.067

Hail, Lincoln

When: July 10, 7:08 PM MST
Where: Lincoln County, 20 mi S of Boyero
Measured: 0.75 in hail
Reported by: TRAINED SPOTTER
Coordinates: 38.650, -103.267

What these are

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.
Hail: Hail three-quarters of an inch or larger, or smaller hail that caused damage, filed with the largest stone measured.

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

The same day elsewhere

Every storm in Colorado in 2002 Every state in 2002 This day in weather history Warnings in Colorado, July 2002

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: 5310037, 5310038, 5309946, 5309947, 5309948, 5309949, 5309950, 5309951, 5309952, 5309953, 5310039, 5310040, 5310041, 5310042, 5310043, 5310044, 5310045, 5310046.