Flash Flood in Wyoming, July 16, 2002

Name: Flash Flood in Wyoming, July 16, 2002
Start: 2002-07-16T13:00
End: 2002-07-16T14:30
Location: Wyoming

July 16, 2002 · NWS RIW · 1 event in 1 county or zone

Strong thunderstorms caused flash flooding across portions of southern Park County. The first area of flash flooding and damage was reported near Valley.

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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The toll

Deaths: 0
Injuries: 0
Property damage: $275,000
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 RIW wrote it up.

Strong thunderstorms caused flash flooding across portions of southern Park County. The first area of flash flooding and damage was reported near Valley. Heavy rain washed out bridges and portions of gravel roads. Also, the heavy rain and runoff resulted in 4 to 5 feet of mud on the roads. The second area of flash flooding and damage occurred between Cody and Wapiti, along Rattlesnake Creek. A 10 foot wall of mud and rock slid through cabins. Also, 1.03 inches of rain fell in Wapiti. The third area of flash flooding and damage occurred west of Meeteetse, near Pitchfork Ranch and Poverty Flats. Two to three bridges were damaged, as well as a 200 yard long, 6 feet wide portion of a road. The Park County Emergency Manager estimated the damage from the flash flooding between $250,000 and $300,000.

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 Riverton, WY wrote its last area forecast discussion before the first event at Jul 16, 1:00 AM MST, 12 hours earlier.

Area forecast discussion, Jul 16, 1:00 AM MST, 12 hours before

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
200 AM MDT TUE JUL 16 2002

THE MONSOON MOISTURE EXPRESS CONTINUES THIS MORNING FROM AZ/NM ON
NORTH ACROSS THE GREAT BASIN...INTO ID/NORTHWEST WY AND MT. MCS
CURRENTLY ACROSS EASTERN MT...WITH A FEW STORMS OVER CENTRAL MT.
TSTMS HAVE EXITED THE RIW CWFA...WITH ONLY A FEW SHWRS REMAINING
OVER YNP.

NOT MUCH CHANGE THROUGH THURSDAY. UPPER RIDGE WILL SLOWLY WEAKEN OVER
THE AREA AND A WEAK UPSLOPE FLOW WILL DEVELOP EAST OF THE DIVIDE BY
WEDNESDAY. BEST INSTABILITY/DYNAMICS WILL REMAIN TO OUR NORTH AND
WEST ACROSS ID AND MT. HOWEVER...NORTH AND WEST CWFA WILL BE CLOSE
ENOUGH TO MOISTURE PLUME FOR CHC POPS TODAY THROUGH THURSDAY. ALSO...
AVN MODEL STILL HAVING CONVECTIVE FEEDBACK PROBLEMS SO ETA QPF
AMOUNTS LOOK BETTER.

WILL NOT MAKE ANY CHANGES TO THE EXTENDED FORECAST.  LOOKS LIKE THE
NORTHWEST CWFA WILL HAVE THE BEST CHC FOR TSTMS AS MONSOON MOISTURE
PLUME WILL BE NEAR BY.

.RIW...NONE.

MC

The radar

The Billings radar (KBLX), 167 km away, was scanning. The volume nearest the first event began at 20:02 UTC.

Open the radar archive at this moment

Event by event

1 flash flood. Local standard time, as filed.

Flash Flood, Park

When: July 16, 1:00 PM MST to 2:30 PM MST
Where: Park County, South Portion
Property damage: $275,000
Reported by: EMERGENCY MANAGER
Coordinates: 44.521, -109.588 (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

Every storm in Wyoming in 2002 Every state in 2002 This day in weather history Warnings in Wyoming, 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: 5303372.