A strengthening pressure gradient generated strong west winds across the Absaroka Range. A few locations experienced gusts over 70 mph.
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.
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 strengthening pressure gradient generated strong west winds across the Absaroka Range. A few locations experienced gusts over 70 mph. At an automated station on Chief Joseph Pass sustained wind speeds of 50 mph or more occurred for the better part of six hours during the evening. The peak sustained speed of 67 mph was recorded at 1820MST.
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 Dec 9, 1:54 PM MST, 3 hours 51 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RIVERTON WY 154 PM MST TUE DEC 9 2008 SHORT TERM...TONIGHT THROUGH FRIDAY TEMPERATURES WILL BE A CHALLENGE TONIGHT AS STEEP INVERSIONS SET UP IN MOST BASIN/VALLEY LOCATIONS WHILE WINDS TRY AND MIX DOWN AND BLOW IN OTHER AREAS. ALSO...SOME LEE ENHANCED CLOUD COVER WILL MOVE DOWN FROM THE NW. HAVE GENERALLY LOWERED TEMPERATURES IN THE FAR WEST VALLEYS AND CENTRAL BASINS...ESPECIALLY AFTER SEEING HOW LOW SOME AREAS GOT THIS MORNING. ALSO RAN OUR DIURNAL OBS TOOL USING NAM12 GUIDANCE TO INDICATE RISING TEMPERATURES IN THE WIND AREAS AFTER THE BRIEF DROP THIS EVENING. WEAK PUSH OF ISENTROPIC LIFT RACES SE ACROSS THE AREA OVERNIGHT WITH JUST A FEW MTN FLURRIES OR BRIEF LIGHT SNOW POSSIBLE. LITTLE OR NO ACCUMULATION. THE GFS WAS FOLLOWED TODAY AND IS SHOWS A BRIEF BREAK IN BETWEEN SYSTEMS WEDNESDAY WHILE A CLIPPER BRUSHES OUR NERN ZONES. ANOTHER AREA OF ISENTROPIC LIFT IMPACTS THE WEST AND POTENTIALLY THE SOUTH ON THURSDAY. THIS SYSTEM APPEARS TO HAVE A LITTLE MORE MOISTURE WITH IT THAN TONIGHTS SYSTEM. IT ALSO APPEARS ANOTHER CLIPPER WILL BRUSH OUR NERN ZONES IN THE AFTERNOON THURSDAY. WE THEN SHOULD SEE A BREAK INTO AT LEAST PART OF FRIDAY BEFORE THE MORE SIGNIFICANT CHANGES BEGIN TO TAKE SHAPE BEYOND THE SHORT TERM PERIOD. THE GFS IS GENERALLY HOLDING OFF ON ANY PCPN IN THE NWRN ZONES UNTIL FRIDAY NIGHT WHILE THE NAM IS ABOUT 12 HOURS FASTER. SINCE OUR FORECAST HAD A CHANCE OF SNOW IN IT FOR FRIDAY...I JUST SLOWED IT DOWN FOR 6 HOURS AND LEFT THE CHANCE POPS IN FOR THE AFTERNOON. TEMPERATURES WILL CONTINUE TO BE A CHALLENGE THROUGH THE SHORT TERM PERIOD WITH INVERSION TRAPPED BASINS AND VALLEYS. ENOUGH GRADIENT MAY DEVELOP FOR AT LEAST PORTIONS OF THE CENTRAL BASINS TO MIX BY FRIDAY. HIGHS WILL ALSO BE HINDERED AT TIMES WITH CLOUD COVER. LONG TERM...FRIDAY NIGHT THROUGH TUESDAY GFS AND ECMWF HAVE BACKED OFF WITH THE COLD FRONT PUSH INTO WY FRIDAY. THUS A MILD DAY ALONG WITH DRY CONDITIONS AT THE LOWER ELEVATIONS. WILL KEEP A CHANCE OF SNOW IN THE WESTERN MTS AS MOISTURE DOES INCREASE IN THE AFTERNOON IN A WEST FLOW ALOFT. THE COLD FRONT INVADES NORTHERN AND WESTERN WY LATE FRI NIGHT. HAVE INCREASED THE SNOW CHANCE IN THE WESTERN MTS FRI NIGHT AS THE FIRST SHORTWAVE SWINGS TOWARD WESTERN WY. CENTRAL AND EAST ZONES STILL LOOK MOSTLY DRY ASIDE FROM LIGHT SNOW DEVELOPING IN THE FAR NORTH LATE FRI NIGHT BEHIND THE FRONTAL PUSH. WILL SEE HOW THINGS LOOK IN UPCOMING MODEL RUNS. THE COLD FRONT SURGES SOUTH ON SATURDAY BRINGING MUCH COLDER TEMPERATURES AND THE CHANCE FOR SNOW BEHIND THE FRONTAL PASSAGE. AGAIN HAVE RAISED PRECIP CHANCES ESPECIALLY IN THE WEST WHERE A MOIST WEST SOUTHWEST FLOW IS FORECAST. SATURDAY NIGHT THROUGH SUNDAY NIGHT LOOK QUITE COLD WITH PERIODS OF LIGHT SNOW MOST PLACES. THE GFS AND ECMWF HAVE SOME DIFFERENCES WITH THE WESTERN TROUGH AND SHORTWAVE TIMING AS PIECES OF ENERGY SWING THROUGH THE TROUGH. HAVE INCREASED THE PRECIP CHANCE MOST AREAS SAT NIGHT THROUGH SUN NIGHT. MONDAY AND TUESDAY LOOK TO BE QUITE COLD WITH SOME LIGHT SNOW AT TIMES PER THE GFS AND ECMWF DESPITE THEIR DIFFERENCES IN TROUGH ORIENTATION BY THAT TIME. STILL A LOT OF UNCERTAINTY ON HOW THIS TROUGH WILL SET UP THIS WEEKEND INTO NEXT WEEK FOR SNOW PRODUCTION. THE MAIN AGREEMENT IS THE FRIGID TEMPS FROM SUNDAY THROUGH TUESDAY. AVIATION... WESTERLY WINDS WILL INCREASE TONIGHT AND CONTINUE THROUGH WEDNESDAY ACROSS THE ABSAROKA MOUNTAINS...EAST SLOPE OF THE WIND RIVER MOUNTAINS...THE BIG HORN MOUNTAINS AS WELL AS SWEETWATER COUNTY. THE STRONGEST WINDS WILL OCCUR ACROSS THE ABSAROKA MOUNTAINS WHERE SUSTAINED WIND SPEEDS WILL BE 30 TO 40 MPH WITH GUSTS AS HIGH AS 50 TO 70 MPH. THERE WILL BE SOME LOCAL SUSTAINED WIND SPEEDS OF 40 TO 60 MPH WITH GUSTS TO 80 TO 90 MPH IN THE ABSAROKA MOUNTAINS. ELSEWHERE ACROSS THE ABOVE MENTIONED AREAS WINDS WILL GENERALLY BLOW AT 20 TO 30 MPH WITH SOME GUSTS TO 40 MPH. OTHERWISE VFR CONDITIONS ARE EXPECTED THROUGH WEDNESDAY. EXPECT CIGS OF 3 TO 4K TO DEVELOP OVER THE FAR WEST LATE TONIGHT THROUGH WEDNESDAY. FIRE WEATHER... ANOTHER COLD NIGHT WITH INCREASING WEST TO SOUTHWEST WIND IN AREAS. THE STRONGEST WIND WILL BE ALONG THE EAST SLOPE OF THE ABSAROKA MOUNTAINS WHERE HIGH WINDS ARE EXPECTED. IT WILL ALSO BECOME WINDY ACROSS INTERSTATE 80 AND OVER TO CASPER. THE BASINS AND VALLEY WILL GENERALLY HAVE STEEP INVERSIONS AND VERY COLD TEMPERATURES AGAIN. WEDNESDAY WILL NOT BE QUITE AS COLD WITH CONTINUED WINDY AREAS AND VALLEY/BASIN INVERSIONS. A FEW FLURRIES OR LIGHT SNOW IS POSSIBLE IN THE NORTHWEST MOUNTAINS. && .RIW WATCHES/WARNINGS/ADVISORIES... HIGH WIND WARNING FROM 5 PM THIS AFTERNOON TO 8 AM MST WEDNESDAY FOR WYZ002. && SHORT TERM...SKRBAC LONG TERM...AR AVIATION...LIPSON FIRE WEATHER...SKRBAC
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE RIVERTON WY 200 PM MST TUE DEC 9 2008 WYZ001>020-022>030-101200- 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- 200 PM MST TUE DEC 9 2008 ...HIGH WIND WARNING FOR THE ABSAROKA MOUNTAINS TONIGHT THROUGH WEDNESDAY MORNING... THIS HAZARDOUS WEATHER OUTLOOK IS FOR WESTERN AND CENTRAL WYOMING. .DAY ONE...TONIGHT VERY STRONG WEST WINDS ARE EXPECTED TO DEVELOP ACROSS THE ABSAROKA MOUNTAINS THIS EVENING AND ARE EXPECTED TO CONTINUE THROUGH THE NIGHT. WIND SPEEDS ARE EXPECTED TO REACH 40 TO 60 MPH WITH GUSTS OF 80 TO 90 MPH ALONG PORTIONS OF THE CHIEF JOSEPH HIGHWAY. LESSER WIND SPEEDS ARE EXPECTED ACROSS THE REST OF THESE MOUNTAINS. THE STRONGEST WINDS ARE EXPECTED TO OCCUR BETWEEN 2 AND 5 AM TONIGHT. IN ADDITION...THESE WINDS WILL CAUSE CONSIDERABLE BLOWING AND DRIFTING SNOW. .DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY VERY STRONG WEST WINDS ARE EXPECTED TO CONTINUE ACROSS THE ABSAROKA MOUNTAINS THROUGH 8 AM TUESDAY. THESE WINDS WILL CAUSE CONSIDERABLE BLOWING AND DRIFTING SNOW. A WINTER STORM MAY BRING SIGNIFICANT SNOWFALL AND MUCH COLDER WEATHER ACROSS WEST AND CENTRAL WYOMING SATURDAY THROUGH MONDAY. THIS WINTER STORM SYSTEM WILL LIKELY HAVE SIGNIFICANT IMPACTS ON TRAVEL AND OUTDOOR ACTIVITIES. STAY TUNED FOR UPDATES ALL WEEK ON THIS WEATHER SITUATION. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION WILL NOT BE NEEDED TODAY AND TONIGHT. TEAM RIVERTON
The national radar mosaic for the moment the first event began.
1 high wind. Local standard time, as filed.
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, December 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: 137263.