A storm system brought heavy snow to the Wind River Mountains and southwest Wyoming. Snowfall amounts ranged from 6 to 9 inches.
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.
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.
The episode as NWS RIW wrote it up.
A storm system brought heavy snow to the Wind River Mountains and southwest Wyoming. Snowfall amounts ranged from 6 to 9 inches.
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 May 10, 1:45 PM MST, 10 hours 15 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RIVERTON WY 245 PM MDT FRI MAY 10 2002 UPPER LEVEL LOW PRESSURE STORM SYSTEM DEVELOPING ON TRACK OVER GREAT BASIN SPREADING INTO WY EARLY THIS AFTERNOON. PRECIPITATION FALLING EVANSTON AND KEMMERER SPREADING EAST ALONG I80 AND OVER HIGHER TERRAIN OF WIND RIVER...SALT AND WY RANGES. AREA OF PRECIPITATION ACROSS S MT ALSO INCREASING AND EXPECTED TO SPREAD SOUTH EARLY MERGING WITH PRECIPITATION FROM S SYSTEM. ALL MODELS BULLS EYE WEST CENTRAL TO EAST CENTRAL WY WITH SIGNIFICANT QPF FROM .75 TO 1.25 TONIGHT AND SATURDAY. TEMPERATURES ALOFT LOOK COLD ENOUGH FOR SNOW MOST AREAS ONCE PRECIPITATION BECOMES WIDESPREAD THIS EVENING. EXPECT SNOWFALL TO BE HEAVY ENOUGH TO ACCUMULATE EXCEPT ON ROADS IN LOWER ELEVATIONS EXCEPT WHERE HEAVY SNOW FALLS FOR AN HOUR OR TWO. WILL KEEP WINTER WEATHER ADVISORY TONIGHT AND SATURDAY AND EXTEND IT THROUGH THE SOUTHWEST WHERE FIRST PRECIPITATION IS OCCURRING AND WHERE HEAVIEST SNOW EXPECTED EARLY THIS EVENING. MODEL TEMPS SEEM WAY TO WARM SATURDAY WITH WIDESPREAD PRECIPITATION/SNOW AND WILL KEEP TEMPERATURES DOWN. WITH WET SNOW EVENT ENDING LATE SATURDAY AFTERNOON/EVENING AND THEN CLEARING...EXPECT FOG FORMATION AND HAVE ADDED FOG LATE SATURDAY NIGHT AND SUNDAY MORNING MOST ZONES. NORTHWEST THIRD OF WY SHOULD BE TOO FAR FROM SIGNIFICANT UPPER DIVERGENCE/LOW LEVEL CONVERGENCE AREA IN CENTRAL WY TO GET ENOUGH SNOW FOR ADVISORY. THERMOPOLIS AREA MAY BE BIGGEST SURPRISE BUT MESO ETA MOISTURE IN BIG HORN BASIN LIMITED. WILL ACCUMULATE SNOW ACROSS NORTH BUT KEEP SNOW AMOUNTS ON THE LIGHT SIDE. COORDINATED WITH CYS AND THEY ARE ISSUING ADVISORY EAST OF NATRONA COUNTY NOW WITH ABOUT THE SAME SNOWFALL FORECAST IN THEIR AREA AS PREVIOUSLY FORECAST TO THE WEST. RIW...WINTER WEATHER ADVISORY TONIGHT AND SATURDAY MOST OF CENTRAL AND SOUTHWEST WY ZONES 08..11>015..17>20..22>25..26>028. C.BAKER
The national radar mosaic for the moment the first event began.
2 heavy snow. Local standard time, as filed.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Wyoming in 2002Every state in 2002This day in weather historyWarnings in Wyoming, May 2002
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: 5293950, 5293951.