Colorado, 2002

Flash Flood in Colorado, September 11, 2002

September 11, 2002 · NWS GJT · 1 event in 1 county or zone

Two deep drainages of 20 to 30 feet deep filled up and overflowed US Highway 50 which extends over the drainages. Water 3 feet deep was running across the highway in some locations with nearly 2 feet of debris deposited on the road.

Where it happened

Every event with a place to put it; 1 filed by county or forecast zone are drawn at its center, in a lighter ring. Tap one for its entry below.

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  • Wind
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  • Cold
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  • Other

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The toll

Deaths
0
Injuries
0
Property damage
$25,000
Crop damage
None recorded
Events
1

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 happened

The episode as NWS GJT wrote it up.

Two deep drainages of 20 to 30 feet deep filled up and overflowed US Highway 50 which extends over the drainages. Water 3 feet deep was running across the highway in some locations with nearly 2 feet of debris deposited on the road. Several unoccupied cars and one occupied car were washed off the road. Other noteworthy items which were washed downstream from nearby farms included a boat, a refrigerator, sheds, 50 gallons drums, and a large gas tank. Snow plows and front end loaders were used to clear the debris and open the highway. Flash flood waters several feet deep also ran across County Road 6.5.

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 Grand Junction, CO wrote its last area forecast discussion before the first event at Sep 11, 1:50 PM MST, 3 hours 40 minutes earlier.

Area forecast discussion, Sep 11, 1:50 PM MST, 3 hours 40 minutes before
WESTERN COLORADO & EASTERN UTAH AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
250 PM MDT WED SEP 11 2002

FLASH FLOODING CONCERNS REMAIN HIGH FOR AREAS OF SOUTHWEST COLORADO
AND SOUTHEAST UTAH AS VERY MOIST SOUTHERLY FLOW CONTINUES OVER THE
REGION.  HAVE HAD SOME MAJOR MUD/DEBRIS FLOWS IN THE MISSIONARY
RIDGE BURN AREA OVER THE PAST 18 HOURS...AND WITH MORE RAIN
EXPECTED...WE HAVE OPTED TO CONT THE FLASH FLOOD WARNING FOR THIS
SITE UNTIL 4 PM THIS AFTERNOON. THE REMAINDER OF SOUTHWEST COLORADO
AND SOUTHEAST UTAH WILL REMAIN UNDER A FLASH FLOOD WATCH UNTIL 10
PM THIS EVENING.

THE UPPER LEVEL LOW OVER WESTERN UTAH WILL BE LIFTING SLOWLY
NORTHEAST OVER THE NEXT 24 HOURS.  DIFFLUENT FLOW...ABUNDANT
SUBTROPICAL MOISTURE AND EMBEDDED WAVES WILL RESULT IN NUMEROUS
SHOWERS AND THUNDERSTORMS THROUGH THE OVERNIGHT HOURS. RADARS OVER
ARIZONA AND NEW MEXICO REMAIN ACTIVE...SO CONFIDENCE IS HIGH THAT
MORE RAIN WILL FALL OVERNIGHT. IN ADDITION...PRECIPITABLE WATER
VALUES ARE RUNNING OVER 150% OF NORMAL ACROSS MUCH OF THE AREA.

ON THURSDAY...FOCUS OF SHOWERS AND THUNDERSTORMS WILL SHIFT NORTH
INTO CENTRAL AND NORTHERN COLORADO AS THE LOW LIFTS OUT AND FLOW
COMES AROUND TO A MORE NORTHWESTERLY COMPONENT.  TROUGH HANGS BACK
OVER THE REGION INTO EARLY FRIDAY...WITH DRIER NWLY FLOW FINALLY
SETTLING INTO THE REGION LATE FRIDAY.  THIS WILL RESULT IN DRIER
WEATHER BY SATURDAY.  TEMPERATURES WILL REMAIN NEAR TO BELOW
SEASONAL NORMS THROUGH THE PERIOD. JDC

EXTENDED (SAT-WED)...MODELS IN GENERAL AGREEMENT WITH RESPECT
TO SENSIBLE WX OVER THE SOUTHWESTERN STATES. SHOULD SEE DRIER
CONDITIONS SATURDAY AS THE FLOW ALOFT BECOMES NORTHWESTERLY...
HOWEVER LEFT ISOLATED POPS OVER THE NORTHERN MOUNTAINS. SHORTWAVE
ENERGY THEN RETURNS SUNDAY AND BACKS THE FLOW ALOFT TO THE
SOUTHWEST. THIS WILL RESULT IN A SLIGHT CHANCE OF TSTMS OR
LIGHT RAIN TO THE NORTHERN MOUNTAINS THROUGH TUESDAY MORNING.
RIDGING RETURNS FOR LATE TUESDAY INTO WEDNESDAY.
MC

.GJT...FLASH FLOOD WATCH THROUGH 10 PM MDT TONIGHT FOR SOUTHWEST
       COLORADO AND SOUTHEAST UTAH.

The radar

The Grand Junction radar (KGJX), 38 km away, was scanning. The volume nearest the first event began at 00:31 UTC.

Open the radar archive at this moment

Event by event

1 flash flood. Local standard time, as filed.

Flash Flood, Delta

When
September 11, 5:30 PM MST to 6:30 PM MST
Where
Delta County, 2 mi NW of Delta
Property damage
$25,000
Reported by
EMERGENCY MANAGER
Coordinates
38.861, -107.863 (the zone’s center; the record gives no point)

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.

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

The same day elsewhere

More

Every storm in Colorado in 2002Every state in 2002This day in weather historyWarnings in Colorado, September 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: 5320918.