A strong Pacific storm system brought heavy snow to western Wyoming and the Bighorn Mountains. Two to three feet of snow fell in the Teton Range and southeast Bighorn Mountains.
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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 strong Pacific storm system brought heavy snow to western Wyoming and the Bighorn Mountains. Two to three feet of snow fell in the Teton Range and southeast Bighorn Mountains. Six to ten inches were common in the western Wyoming valleys. Widespread strong to high wind accompanied this system with gusts of 60 to 70 mph across many lower elevations east of the Continental Divide. Gusts over 100 mph were recorded in the western Wyoming mountains.
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 Feb 20, 2:49 PM MST, 1 hour 1 minute earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RIVERTON WY 249 PM MST MON FEB 20 2012 .SHORT TERM...TONIGHT THROUGH THURSDAY A SERIES OF INCREASING PACIFIC TROUGHS WILL SHOVE THE RIDGE IN THE EASTERN PACIFIC SOUTH AS A STRONG PACIFIC JET MOVES INLAND. THE FIRST TROUGH WILL BRING INCREASED LIGHT SNOW TO THE WEST THROUGH THE NIGHT AS WESTERLY WINDS PICK UP. BY MIDNIGHT THE THREAT OF HIGH WINDS WILL DEVELOP ALONG AND NEAR THE EAST SLOPES OF THE ABSAROKA MOUNTAINS AND EAST OF TOGWOTEE PASS IN THE UPPER WIND RIVER AREA THROUGH DUBOIS TO NEAR CROWHEART. TUESDAY WILL SEE INCREASED SNOWFALL IN THE WEST WITH PERIODS OF MODERATE TO HEAVY SNOW WITH STRONG WINDS. SOME OF THE VALLEYS MAY SEE RAIN OR A RAIN SNOW MIX IN THE AFTERNOON AROUND AFTON AND JACKSON AND THE NORTHERN PART OF YELLOWSTONE NATIONAL PARK ALONG THE LAMAR VALLEY. SNOWFALL IS EXPECTED ACROSS THE WEST WITH ACCUMULATIONS OF TWO TO THREE FEET IN THE TETONS THROUGH WEDNESDAY NIGHT. THE OTHER MOUNTAINS OF THE WEST SHOULD SEE ONE TO TWO FEET OF SNOW. TUESDAY NIGHT AND WEDNESDAY MOUNTAIN TOP WINDS OF 50 TO 60 MPH WITH GUSTS TO 90 MPH WILL BE POSSIBLE WITH SIGNIFICANT BLOWING SNOW ON THE PASSES, HIGH WINDS WILL SPREAD SOUTH AND EAST WITH HIGH WINDS ALONG THE EAST SLOPES OF THE WIND RIVER MOUNTAINS INTO THE LANDER FOOTHILLS. THESE WINDS WILL SPREAD EAST FROM SOUTH PASS THROUGH BEAVER RIM TO MUDDY GAP ACROSS THE GREEN AND RATTLESNAKE MOUNTAINS AND ACROSS NATRONA COUNTY AND EASTERN SWEETWATER COUNTY. HIGH WIND WATCHES AND WINTER STORM WATCHES HAVE BEEN ISSUED. AREAS ACROSS THE WIND RIVER BASIN AND THE UPPER GREEN RIVER BASIN MAY SEE HIGH WINDS BUT THIS IS MUCH LESS CERTAIN AND THEY ARE NOT CURRENTLY IN THE FORECAST. STRONG WINDS WILL ALSO BE POSSIBLE ALONG THE EAST SLOPES OF THE BIGHORN MOUNTAINS BUT HIGH WINDS ARE NOT CURRENTLY FORECAST THERE EITHER. THESE AREAS WILL NEED TO BE WATCHED AS CONDITIONS MAY BECOME MORE FAVORABLE FOR HIGH WINDS IN THESE AREAS. IN THE WEST THE SNOW LINE WILL BE MOST CRITICAL IN THE STAR VALLEY AND JACKSON HOLE. HEAVY VALLEY SNOWFALL MAY OCCUR IF THE TEMPERATURES END UP ONLY A FEW DEGREES COLDER. TEMPERATURES WILL BE DIFFICULT THROUGH THE FORECAST PERIOD WITH PRECIPITATION...CLOUD COVER AND VIGOROUS MIXING WITH A STRONG JET PASSING OVER THE AREA. SNOWFALL WILL TAPER OFF OVER THE WEST WEDNESDAY NIGHT BUT CONDITIONS MAY NOT IMPROVE UNTIL THE WINDS DECREASE AS WELL TOWARDS THURSDAY MORNING. COLDER TEMPERATURES WILL MOVE IN WEDNESDAY NIGHT AND THURSDAY AS THE UPPER LEVEL TROUGH AND COLD FRONT MOVE EAST OF THE AREA. .LONG TERM...THURSDAY NIGHT THROUGH MONDAY STRONG NORTHWEST FLOW TO REMAIN OVER THE FORECAST AREA THURSDAY NIGHT...WITH CONTINUED SNOWFALL EXPECTED..ESPECIALLY OVER THE NORTHERN THIRD OF THE FORECAST AREA. MODELS IN FAIR AGREEMENT WITH THIS BEGINNING OF THE FORECAST PERIOD. SOME VARIANCE IN MODELS BEGINS ON FRIDAY EVENING. THE GFS BRING THE AXIS OF A RIDGE THROUGH THE AREA BY FRIDAY EVENING...WHILE THE ECMWF KEEPS THE AXIS FURTHER WEST BY THIS TIME. BOTH MODELS AGREE THAT SNOWFALL WILL BE POSSIBLE OVER THE NORTHWEST...THOUGH THE ECMWF IS THE MORE AGGRESSIVE MODEL ON COVERAGE AT THIS TIME. THOUGH THE DIFFERENCE IN THE DEPARTURE OF THE NORTHWEST FLOW EXISTS BETWEEN THE MODELS... THEY BOTH GENERATE THE POTENTIAL FOR ANOTHER WIDESPREAD SNOWFALL EVENT BY SATURDAY AFTERNOON. THE GFS HAS THIS RESULT FROM A WAVE OF LOW PRESSURE MOVING THROUGH THE AREA WITH SOUTHWEST FLOW. THE ECMWF HAS MORE OF A ZONAL FLOW ACROSS THE AREA WITH A WEAKER WAVE EMBEDDED IN THE FLOW. MODELS THEN COME INTO BETTER AGREEMENT BY SUNDAY AFTERNOON WITH BOTH SHOWING A STRONG WAVE OF LOW PRESSURE MOVING THROUGH THE CWA. THE GFS IS THE QUICKER MODEL TO MOVE THIS SNOWFALL OUT OF THE AREA...WHILE THE ECMWF KEEPS SNOWFALL PRESENT THROUGH MONDAY. && .AVIATION.../00Z ISSUANCE/ WEST OF THE DIVIDE...POTENTIALLY SIGNIFICANT SNOWFALL WILL BEGIN BETWEEN 06Z AND 09Z TONIGHT ACROSS THE WESTERN VALLEYS. THIS SNOWFALL...WHICH WILL BE HEAVY AT TIMES...WILL CAUSE PERIODS OF MVFR TO IFR CONDITIONS. LIFR CONDITIONS WILL ALSO BE POSSIBLE IN THE HEAVIER SNOWFALL...WHICH IS ANTICIPATED AFTER 12Z TUESDAY OVER KJAC. SNOWFALL WILL CONTINUE THROUGH THE FORECAST PERIOD...AND IS ANTICIPATED TO IMPACT ALL TERMINALS WEST OF THE DIVIDE...WITH KBPI AND KRKS SEEING THE LATEST INITIATION TIMES. MOUNTAINS WILL REMAIN OBSCURED IN SNOWFALL AND LOW CLOUDS...AND MOUNTAIN PASSES MAY EXPERIENCE INCREASED ICING AND TURBULENCE. EAST OF THE DIVIDE...GENERAL VFR CONDITIONS WILL PERSIST THROUGH MUCH OF THE FORECAST PERIOD. SOME SNOWFALL MAY MOVE EAST OF THE DIVIDE AFTER 18Z TUESDAY...THOUGH SNOWFALL SHOULD REMAIN LIGHT WITH PERIODS OF MVFR CONDITIONS BEING THE BIGGEST IMPACT. THE BIGGER ITEM OF INTEREST EAST OF THE DIVIDE WILL BE WIND...WHICH MAY INCREASE TO BECOME STRONG BETWEEN 18Z AND 21Z TUESDAY. STRONG WIND WILL ESPECIALLY IMPACT KCPR...KCOD...KLND...AND KU25 DURING THE FORECAST PERIOD. OTHER AREAS WILL ALSO SEE INCREASED WIND...INCLUDING KRIW. && .FIRE WEATHER... SNOW WILL INCREASE ACROSS THE WEST TONIGHT. WINDS WILL INCREASE ACROSS THE AREA. AFTER MIDNIGHT AREAS OF HIGH WINDS WILL BE POSSIBLE ALONG THE EAST SLOPES OF THE ABSAROKA MOUNTAINS AND CODY FOOTHILLS AROUND CLARK. HIGH WINDS MAY ALSO DEVELOP FROM TOGWOTEE PASS THROUGH DUBOIS TO NEAR CROWHEART. SNOWFALL WILL PICK UP ACROSS THE WEST TUESDAY ALONG WITH STRONG RIDGE TOP WINDS. A WINTER STORM WATCH IS IN EFFECT FOR MUCH OF THE WEST TUESDAY THROUGH WEDNESDAY NIGHT. THE WESTERN VALLEYS MAY SEE RAIN DURING THE DAY LIMITING SNOWFALL AMOUNTS. IF THE TEMPERATURES END UP COOLER...SIGNIFICANT VALLEY SNOW WILL OCCUR. HIGH WINDS ARE EXPECTED OVER MUCH OF THE AREA EAST OF THE CONTINENTAL DIVIDE TUESDAY NIGHT INTO WEDNESDAY EVENING. MIXING HEIGHTS WILL BE LOW WEST OF THE CONTINENTAL DIVIDE WITH POOR SMOKE DISPERSAL. EAST OF THE DIVIDE...AS WINDS INCREASE...MIXING WILL DEEPEN WITH SOME AREAS SEEING GOOD SMOKE DISPERSAL IN THE AFTERNOON. && .RIW WATCHES/WARNINGS/ADVISORIES... HIGH WIND WATCH FROM LATE TUESDAY NIGHT THROUGH WEDNESDAY EVENING WYZ015-018>020-030. WINTER STORM WATCH FROM LATE TONIGHT THROUGH LATE WEDNESDAY NIGHT WYZ001-012-014-024. HIGH WIND WARNING FROM MIDNIGHT TONIGHT TO 8 PM MST WEDNESDAY WYZ002-003-016. && SHORT TERM...C.BAKER LONG TERM...BRANHAM AVIATION...BRANHAM FIRE WEATHER...C.BAKER
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE RIVERTON WY 1244 PM MST MON FEB 20 2012 WYZ001>020-022>030-211430- 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- 1244 PM MST MON FEB 20 2012 ...HIGH WIND WATCH FOR IN AND NEAR THE EAST SLOPES OF THE MOUNTAINS LATE TONIGHT THROUGH WEDNESDAY EVENING... ...WINTER STORM WATCH FOR THE WESTERN MOUNTAINS TUESDAY THROUGH WEDNESDAY NIGHT... THIS HAZARDOUS WEATHER OUTLOOK IS FOR WESTERN AND CENTRAL WYOMING. .DAY ONE...TODAY AND TONIGHT STRONG WINDS ARE EXPECTED TO DEVELOP ALONG AND NEAR THE EAST SLOPES OF THE ABSAROKA AND WIND RIVER MOUNTAINS THROUGH THE NIGHT. HIGH WINDS MAY DEVELOP AROUND CLARK AND DUBOIS. SNOWFALL WILL INCREASE ACROSS THE WESTERN MOUNTAINS AND VALLEYS THROUGH THE NIGHT. .DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY .TUESDAY THROUGH THURSDAY...PERIODS OF SNOW AND STRONG WINDS FOR THE WESTERN AND NORTHERN WYOMING MOUNTAINS. AREAS OF VERY STRONG WIND EXPECTED EAST OF THE CONTINENTAL DIVIDE TUESDAY NIGHT THROUGH WEDNESDAY NIGHT. .SATURDAY...ANOTHER STORM SYSTEM TO BRING SNOW TO WESTERN WYOMING. .SUNDAY...A STRONG COLD FRONT WILL LIKELY BRING SNOW TO MUCH OF THE AREA WITH SHARPLY COLDER TEMPERATURES. .SPOTTER INFORMATION STATEMENT... SPOTTERS ARE ENCOURAGED TO REPORT SNOW AMOUNTS FROM SUNDAY'S STORM. THANK YOU. TEAM RIVERTON
The national radar mosaic for the moment the first event began.
14 high wind, 10 winter storm. Local standard time, as filed.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Wyoming in 2012Every state in 2012This day in weather historyWarnings in Wyoming, February 2012
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: 360448, 360443, 360459, 361110, 360463, 360462, 360460, 360444, 360456, 360458, 360457, 360464, 360461, 360446, 360453, 360447, 361131, 360451, 360455, 360452, 360445, 360454, 360449, 360450.