Thunderstorms formed in unstable, moist southwest flow ahead of an approaching storm system tracking through the Intermountain West.
Every event with a place to put it. 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.
Thunderstorms formed in unstable, moist southwest flow ahead of an approaching storm system tracking through the Intermountain West.
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 Sep 10, 2:13 PM MST, 1 hour 47 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RIVERTON WY 313 PM MDT WED SEP 10 2008 .SHORT TERM...TONIGHT THROUGH FRIDAY NIGHT A COLD STORM SYSTEM WILL MOVE ACROSS WESTERN AND CENTRAL WYOMING TONIGHT THROUGH THURSDAY. THE STORM WILL BRING SNOW TO THE NORTHERN...WESTERN AND CENTRAL MOUNTAINS. SNOWFALL OF 3 TO 6 INCHES IS EXPECTED ABOVE 8500 FEET IN THE NORTHERN...WESTERN AND CENTRAL MOUNTAINS OF WYOMING...INCLUDING THE BIG HORN MOUNTAINS... THE WIND RIVER RANGE...THE ABSAROKA MOUNTAINS AND THE NORTHERN GROS VENTRE MOUNTAINS. LOCALLY HIGHER AMOUNTS OF 6 TO 9 INCHES CAN BE EXPECTED ABOVE 10000 FEET. AREAS FROM 7500 TO 8500 FEET CAN EXPECT 1 TO 3 INCHES OF SNOW. THE STORM WILL BRING EVENING THUNDERSTORMS TO THE AREA ALONG WITH HIGHER HUMIDITY AND COLDER TEMPERATURES. MUCH OF THE AREA IS EXPECTED TO RECEIVE WETTING PRECIPITATION TONIGHT AND THURSDAY. DRYING WILL MOVE IN FROM THE NORTHWEST SPREADING EAST ON THURSDAY NIGHT AND FRIDAY. THE AMOUNT OF DRYING MAY BE OVERDONE WITH NORTHWEST FLOW...BUT AT THIS TIME THE MODELS INDICATE THAT NO PRECIPITATION WILL OCCUR THEN, TEMPERATURES WILL WARM SLIGHTLY ON FRIDAY. FREEZING TEMPERATURES WILL BE MORE WIDESPREAD WITH CLEARING FRIDAY NIGHT. .LONG TERM...SATURDAY THROUGH WEDNESDAY SATURDAY LOOKS DRY EXCEPT FOR A FEW AFTERNOON SHOWERS IN THE BIGHORN MTS AND NORTHERN JOHNSON COUNTY WITH A SHORTWAVE MOVING ACROSS EASTERN MONTANA AND A COLD FRONT THAT PUSHES INTO NORTHERN WY SAT AFTERNOON. DID NOT PUT SHOWERS IN AFTER 00Z SUNDAY BUT THAT CAN BE LOOKED AT AGAIN TODAY. FOLLOWED THE WETTER ECMWF MODEL VERSUS THE DRY GFS MODEL WITH RESPECT TO THE PRECIP CHANCE SAT PM. FORECAST LOOKS DRY SUNDAY THROUGH TUESDAY WITH UPPER HIGH PRESSURE BLOCKING ANY MOISTURE FROM THE AREA. SOME MOISTURE MAY RETURN TO THE AREA NEXT WED AS A WEAK SHORTWAVE IS FORECAST TO MOVE ACROSS THE REGION. ADDED A FEW MOUNTAIN SHOWERS TO NEXT WED. AS FOR TEMPS...SEASONAL HIGHS AND LOWS FOR THE MOST PART THROUGH THE PERIOD WITH A WARMING TREND FROM SUNDAY THROUGH TUESDAY. THEN SLIGHTLY COOLER NEXT WED. && .AVIATION... AN UPPER LOW WILL MOVE INTO EASTERN IDAHO AND WESTERN WYOMING TONIGHT. THIS WILL BRING SCATTERED TO NUMEROUS SHOWER AND THUNDERSTORM ACTIVITY TO THE WEST AND CENTRAL THIS EVENING. EXPECT MVFR CIGS AND VSBYS UNDER LOW CLOUD...HEAVY RAIN AND POSSIBLY SMALL HAIL. STEADIER PRECIPITATION WILL DEVELOP EAST OF THE DIVIDE THIS EVENING WITH WIDESPREAD MVFR CIGS AND LCL VSBYS. SNOW IS EXPECTED ABOVE 8000 FEET MSL. THIS WILL GRADUALLY DIMINISH LATE MORNING BUT COULD HANG ON INTO THE AFTERNOON ACROSS THE NORTH AND EAST. THE LOW CLOUD WILL HANG ON THROUGH MUCH OF THE DAY THURSDAY...LIFTING LATE IN THE AFTERNOON. && .FIRE WEATHER... A COLD STORM SYSTEM WILL MOVE ACROSS WESTERN AND CENTRAL WYOMING TONIGHT THROUGH THURSDAY. THE STORM WILL BRING SNOW TO THE NORTHERN...WESTERN AND CENTRAL MOUNTAINS. SNOWFALL OF 3 TO 6 INCHES IS EXPECTED ABOVE 8500 FEET IN THE NORTHERN...WESTERN AND CENTRAL MOUNTAINS OF WYOMING...INCLUDING THE BIG HORN MOUNTAINS... THE WIND RIVER RANGE...THE ABSAROKA MOUNTAINS AND THE NORTHERN GROS VENTRE MOUNTAINS. LOCALLY HIGHER AMOUNTS OF 6 TO 9 INCHES CAN BE EXPECTED ABOVE 10000 FEET. AREAS FROM 7500 TO 8500 FEET CAN EXPECT 1 TO 3 INCHES OF SNOW. THE STORM WILL BRING EVENING THUNDERSTORMS TO THE AREA ALONG WITH HIGHER HUMIDITY AND COLDER TEMPERATURES. MUCH OF THE AREA IS EXPECTED TO RECEIVE WETTING PRECIPITATION TONIGHT AND THURSDAY. && .RIW WATCHES/WARNINGS/ADVISORIES... NONE. && SHORT TERM...C.BAKER LONG TERM...AR AVIATION...TWB FIRE WEATHER...C.BAKER
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE RIVERTON WY 500 AM MDT WED SEP 10 2008 WYZ001>020-022>030-111200- ABSAROKA MOUNTAINS-BIGHORN MOUNTAINS SOUTHEAST- BIGHORN MOUNTAINS WEST-CASPER MOUNTAIN-CODY FOOTHILLS- EAST SWEETWATER COUNTY-FLAMING GORGE- GREEN MOUNTAINS AND RATTLESNAKE RANGE-JACKSON HOLE-LANDER FOOTHILLS- NATRONA COUNTY LOWER ELEVATIONS-NORTH BIG HORN BASIN- NORTHEAST JOHNSON COUNTY-OWL CREEK AND BRIDGER MOUNTAINS- ROCK SPRINGS AND GREEN RIVER-SALT RIVER AND WYOMING RANGES- SOUTH LINCOLN COUNTY-SOUTHEAST BIG HORN BASIN- SOUTHEAST JOHNSON COUNTY-SOUTHWEST BIG HORN BASIN-STAR VALLEY- TETON AND GROS VENTRE MOUNTAINS-UPPER GREEN RIVER BASIN- UPPER GREEN RIVER BASIN FOOTHILLS-UPPER WIND RIVER BASIN- WIND RIVER BASIN-WIND RIVER MOUNTAINS EAST-WIND RIVER MOUNTAINS WEST- YELLOWSTONE NATIONAL PARK- 500 AM MDT WED SEP 10 2008 THIS HAZARDOUS WEATHER OUTLOOK IS FOR WESTERN AND CENTRAL WYOMING. .DAY ONE...TODAY AND TONIGHT ISOLATED THUNDERSTORMS ARE EXPECTED ACROSS WESTERN AND CENTRAL WYOMING TODAY. THE STRONGEST THUNDERSTORMS ARE EXPECTED IN SOUTHWEST WYOMING THIS AFTERNOON WHERE 40 MPH WIND GUSTS...SMALL HAIL...AND FREQUENT DANGEROUS CLOUD TO GROUND LIGHTNING WILL BE POSSIBLE. RAIN IS EXPECTED TO TURN TO SNOW ABOVE 7000 FEET LATER TONIGHT ACROSS THE MOUNTAINS OF WESTERN AND CENTRAL WYOMING WITH MOST OF THE SNOW FALLING ACROSS THE NORTHERN MOUNTAINS. .DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY UP TO 4 INCHES OF SNOWFALL MAY OCCUR AT ELEVATIONS ABOVE 7000 FEET ACROSS THE MOUNTAINS OF WESTERN AND CENTRAL WYOMING THURSDAY THROUGH THURSDAY NIGHT. UP TO 7 INCHES OF SNOWFALL MAY OCCUR AT ELEVATIONS ABOVE 9000 FEET DURING THIS TIME FRAME. ANYONE TRAVELING OVER ANY MAJOR MOUNTAIN PASSES EAST OF THE DIVIDE INCLUDING TOGWOTEE...POWDER RIVER...GRANITE...AND SOUTH PASS SHOULD ANTICIPATE SLICK AND SNOW COVERED ROADWAYS THURSDAY THROUGH THURSDAY NIGHT. .SPOTTER INFORMATION STATEMENT... SPOTTERS ARE ENCOURAGED TO REPORT WIND GUSTS OVER 40 MPH AS WELL AS ANY HIGH ELEVATION SNOWFALL AMOUNTS. THANK YOU. TEAM RIVERTON
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE RIVERTON WY 1229 PM MDT WED SEP 10 2008 WYZ012-013-101930- JACKSON HOLE-TETON AND GROS VENTRE MOUNTAINS- 1229 PM MDT WED SEP 10 2008 ANOTHER GROUP OF THUNDERSTORMS WILL MOVE OFF THE TETONS AND INTO JACKSON HOLE THROUGH 100 PM. THE STORMS WILL BE IN WILSON... TETON VILLAGE AND COLTER BAY AROUND 1230 PM AND IN JACKSON...MOOSE AND MORAN AROUND 1240 PM. EXPECT A FEW LIGHTNING STRIKES AND SOME BRIEF HEAVY RAIN. WYZ016-101930- UPPER WIND RIVER BASIN- 1229 PM MDT WED SEP 10 2008 A LINE OF THUNDERSTORMS WILL MOVE OFF TOGWOTEE PASS AND INTO THE UPPER WIND RIVER BASIN THROUGH 130 PM. THE STORMS WILL BE IN DUBOIS BETWEEN 1245 AND 100 PM. EXPECT A FEW LIGHTNING STRIKES AND SOME HEAVY RAIN. WYZ003-101930- CODY FOOTHILLS- 1229 PM MDT WED SEP 10 2008 A FEW SHOWERS AND THUNDERSTORMS WILL MOVE OFF THE ABSAROKAS AND INTO THE CODY FOOTHILLS THROUGH 130 PM. CODY...MEETEETSE AND POWELL CAN EXPECT THE SHOWERS AND THUNDERSTORMS. EXPECT A FEW LIGHTNING STRIKES AND SOME BRIEF HEAVY RAIN.
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE RIVERTON WY 1237 PM MDT WED SEP 10 2008 WYZ025-026-101930- UPPER GREEN RIVER BASIN-UPPER GREEN RIVER BASIN FOOTHILLS- 1237 PM MDT WED SEP 10 2008 A LINE OF SHOWERS AND THUNDERSTORMS WILL MOVE ACROSS THE CENTRAL UPPER GREEN RIVER BASIN THROUGH 130 PM. THE STORMS WILL SOUTH AND EAST PINEDALE...MOVING ACROSS BOULDER AN JONAH. EXPECT OCCASIONAL LIGHTNING STRIKES AND SOME BRIEF HEAVY RAIN. WIND GUSTS TO 35 MPH IS ALSO POSSIBLE.
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE RIVERTON WY 1240 PM MDT WED SEP 10 2008 WYZ027-101930- SOUTH LINCOLN COUNTY- 1240 PM MDT WED SEP 10 2008 A LINE OF SHOWERS AND THUNDERSTORMS WILL MOVE ACROSS SOUTHERN LINCOLN COUNTY THROUGH 130 PM. THE STORMS WILL MOVE THROUGH KEMMERER...COKEVILLE...SAGE AND OPAL. EXPECT OCCASIONAL LIGHTNING STRIKES AND SOME BRIEF HEAVY RAIN. WIND GUSTS TO 35 MPH ARE ALSO POSSIBLE. WYZ023-101930- STAR VALLEY- 1240 PM MDT WED SEP 10 2008 A FEW SHOWERS AND THUNDERSTORMS WILL MOVE ACROSS THE STAR VALLEY THROUGH 130 PM. EXPECT OCCASIONAL LIGHTNING STRIKES AND SOME BRIEF HEAVY RAIN. WIND GUSTS TO 35 MPH ARE ALSO POSSIBLE.
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE RIVERTON WY 132 PM MDT WED SEP 10 2008 WYZ027-102100- SOUTH LINCOLN COUNTY- 132 PM MDT WED SEP 10 2008 SCATTERED SHOWERS AND THUNDERSTORM WILL CONTINUE TO MOVE ACROSS SOUTHERN LINCOLN COUNTY THROUGH 3 PM. EXPECT OCCASIONAL LIGHTNING STRIKES AND SOME BRIEF HEAVY RAIN. WIND GUSTS TO 35 MPH ARE ALSO POSSIBLE. WYZ025-102100- UPPER GREEN RIVER BASIN FOOTHILLS- 132 PM MDT WED SEP 10 2008 SCATTERED SHOWERS AND THUNDERSTORM WILL CONTINUE TO MOVE ACROSS NORTHERN SUBLETTE COUNTY. THIS INCLUDES BONDURANT...KENDALL AND GREEN RIVER LAKES. EXPECT OCCASIONAL LIGHTNING STRIKES AND SOME BRIEF HEAVY RAIN. WIND GUSTS TO 35 MPH ARE ALSO POSSIBLE.
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE RIVERTON WY 159 PM MDT WED SEP 10 2008 WYZ007-017-102100- OWL CREEK AND BRIDGER MOUNTAINS-WIND RIVER BASIN- 159 PM MDT WED SEP 10 2008 A STRONG THUNDERSTORM LOCATED OVER THE WESTERN OWL CREEK MOUNTAINS WAS MOVING SOUTHEAST ALONG THE CREST OF THE RANGE. THIS STORM WILL PRODUCE VERY HEAVY RAIN AS WELL AS HALF INCH HAIL STONES. SOME LIGHTNING AND GUSTY WINDS ARE POSSIBLE AS WELL. OTHER STORMS WERE LOCATED IN THE VICINITY OF CROWHEART AND BURRIS. THESE STORMS WILL PRODUCE HEAVY RAIN...OCCASIONAL LIGHTNING AND POSSIBLY SOME SMALL HAIL. THESE STORMS WILL IMPACT THE WIND RIVER BASIN MAINLY NORTH OF HIGHWAY 26...EAST OF DIVERSION.
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE RIVERTON WY 227 PM MDT WED SEP 10 2008 WYZ025-026-102200- UPPER GREEN RIVER BASIN-UPPER GREEN RIVER BASIN FOOTHILLS- 227 PM MDT WED SEP 10 2008 SHOWERS AND THUNDERSTORM WILL MOVE ACROSS THE UPPER GREEN BASIN THIS AFTERNOON. THUNDERSTORMS BETWEEN CORA...PINEDALE AND BOULDER WILL PRODUCE SOME SMALL HAIL...HEAVY RAIN AND FREQUENT LIGHTNING. OTHER STORMS WILL PRODUCE HEAVY RAIN AND OCCASIONAL LIGHTNING WITH SOME SMALL HAIL POSSIBLE.
The Riverton/Lander radar (KRIW), 111 km away, was scanning. The volume nearest the first event began at 22:59 UTC.
1 funnel cloud. Local standard time, as filed.
The general public provided multiple reports of a funnel cloud between Pinedale and Boulder. The funnel quickly dissipated, but was clearly seen from U.S. Highway 191 between the two communities.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Wyoming in 2008Every state in 2008This day in weather historyWarnings in Wyoming, September 2008
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: 129969.