Two snowmobilers were buried in an avalanche on Teton Pass around 1230MST on Thursday, December 24. The pair were on a steep, east-facing slope of the Horseshoe Bowl at about 9,500 feet elevation when the hard slab avalanche broke above them.
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The episode as NWS RIW wrote it up.
Two snowmobilers were buried in an avalanche on Teton Pass around 1230MST on Thursday, December 24. The pair were on a steep, east-facing slope of the Horseshoe Bowl at about 9,500 feet elevation when the hard slab avalanche broke above them. The slide, up to five feet deep, buried both snowmobilers. It took one of them at least three hours to dig himself free after he was buried under three feet of snow. He then came to the rescue of the second person who had suffered a broken leg. The avalanche danger was high due to recent heavy snow of two or more feet in the Teton Range.
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 24, 10:12 AM MST, 2 hours 18 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RIVERTON WY 1012 AM MST THU DEC 24 2015 .SHORT TERM...TODAY THROUGH SATURDAY NIGHT ...A WHITE CHRISTMAS APPEARS LIKELY ACROSS MOST OF WESTERN AND CENTRAL WYOMING... LIGHT SNOW HAS BROKEN OUT ONCE AGAIN IN THE FAR WEST. THIS SNOWFALL WILL INCREASE DURING THE DAY TODAY AS A WEAK VORT LOBE TRACKS RAPIDLY EAST ACROSS WYOMING IN THE FAST BACKING WESTERLY FLOW TODAY. SUB ADVISORY AMNTS OF SNOW ARE EXPECTED WITH THIS WX SYSTEM. THEN WE CAN EXPECT A SHORT RESPITE FROM ANY SIGNIFICANT SNOW TONIGHT. THE TROUGH NOW MAKING LANDFALL UPON THE PACIFIC COAST CONTINUES TO AMPLIFY AND WILL CLOSE OFF RIGHT OVER WY FRIDAY ACDG TO THE GFS. THE H7 CIRCULATION WILL FORM OVER SOUTHEAST IDAHO 06Z FRIDAY AND WILL TRACK TO SWEETWATER COUNTY BY 18Z FRIDAY. THE NAM IS FAIRLY SIMILAR WITH THESE FEATURES BUT IS DRIER WITH THE RESULTS. THE EURO PLACES THE H7/H5 FEATURES FARTHER SOUTH WHICH WOULD GIVE WY LESS OVERALL DYNAMICS TO WORK WITH BUT A DEEPER UPSLOPE FLOW WILL RESULT. EITHER WAY...IT APPEARS THAT SOUTHERN...CENTRAL AND EASTERN WYOMING WILL SEE A WHITE CHRISTMAS WITH THE WEST ALREADY WHITE. A BROAD AREA OF ISENTROPIC LIFT WRAPPING AROUND THE LOW WILL DELIVER WIDESPREAD SNOW FALL TO MAINLY SOUTHERN AND CENTRAL WY EAST OF THE DVD FRIDAY AND THEN EASTERN WY BY FRIDAY EVENING. THESE SNOW PRODUCING CLOUDS WILL SEED THE LOWER DECK OF UPSLOPE ENHANCED CLOUDS THAT WILL FORM NORTH OF THE COLORADO SFC LOW...EAST OF THE DVD...AND WILL ENHANCE UPSLOPE SNOWFALL FROM LND TO CPR FRIDAY AND FRIDAY EVENING. WENT ON THE CAUTIOUS SIDE FOR SNOW AMOUNTS THIS TIME AROUND WITH THE CONTINUED DIFFERENCES IN THE MODELS. THE END RESULT HAS LED TO A FORECAST OF 3 TO 5 INCHES ON THE EAST SLOPE OF THE WIND RVR MTNS...CASPER MTN AND THE SOUTHERN BIG HORN MTNS...2 TO 4 INCHES IN THE FOOTHILLS INCLUDING LANDER ALONG WITH 1 TO 2 INCHES MOST EVERYWHERE ELSE INCLUDING AREAS WEST OF THE DVD FRIDAY. A COLD FRONT WILL DROP SOUTH ACROSS THE AREA FRIDAY AS WELL ALONG WITH H7 TEMPS DROPPING FROM -14C TO -16C GIVING US A SNOW TO WATER RATION OF ONE TO 16. YNP AND THE NORTHERN BIG HORN BASIN WILL NOT SEE AS MUCH ACCUMULATION AS THESE LOCATIONS WILL BE TOO FAR NORTHWEST OF THE DYNAMICS. THEN BY 06Z SATURDAY...THE ENERGY WILL QUICKLY PROPAGATE TO THE SOUTHERN STREAM IN THE DESERT SOUTHWEST WITH CLEARING FROM WEST TO EAST. SATURDAY WILL FEATURE A DRY AND COLD DAY WITH HIGHS REMAINING IN THE TEENS JUST ABOUT EVERYWHERE. THEN ON SATURDAY NIGHT...A FOLD OVER RIDGE WILL INITIATE WARMING ALOFT FROM THE NW...A GOOD SCENARIO FOR FOG DEVELOPMENT UNDER A STRONG TEMPERATURE INVERSION...IN SPITE OF THE NOT SO IMPRESSIVE FCST SOUNDINGS... GIVEN THE FRESH SNOW COVER AND COLD AIR IN PLACE. WE WENT WITH PATCHY FOG FOR LATE SATURDAY NIGHT FOR THE WESTERN AND CENTRAL BASINS AND VALLEYS. IN ADDITION...MANY AREAS...ESPECIALLY THE BASINS AND VALLEYS...WILL EXPERIENCE THE COLDEST TEMPERATURES THUS FAR THIS SEASON WITH SOME WESTERN VALLEYS AND BASINS EXPERIENCING 20 TO 30 BELOW ZERO READINGS BY 12Z SUNDAY. .LONG TERM...SUNDAY THROUGH THURSDAY SOME FAIRLY SIGNIFICANT CHANGES IN THE MEDIUM RANGE TONIGHT COMPARED TO WHAT THE MODELS HAD BEEN SINGING THE LAST FEW NIGHTS. THE BUILDING HEIGHTS REMAIN MORE ALONG AND JUST OFF THE WEST COAST LEAVING THE ROCKIES SUSCEPTIBLE TO DISTURBANCES DROPPING S AND SE INTO THE REGION MOST OF NEXT WEEK. IT STILL LOOKS LIKE WE START OUT THE WEEK WITH SOME STEEP TEMPERATURE INVERSIONS AS RIDGE BUILDS IN BRIEFLY AND FOLDS OVER ACROSS THE STATE RESULTING IN STRONG MID LEVEL WARMING. BASINS AND VALLEYS SHOULD START OUT QUITE COLD SUNDAY MORNING WITH THIS SCENARIO AND ESPECIALLY WITH ALL THE RECENT FRESH SNOW AND EXPECTED SNOW FOR PARTS OF CENTRAL WYO AGAIN ON CHRISTMAS. PATTERN ALREADY STARTS TO GET CHAOTIC AS EARLY AS MONDAY AS FIRST SHORTWAVE DROPS SWD INTO THE WRN GREAT BASIN/DESERT SW MONDAY INTO MONDAY NIGHT. THE ECMWF IS THE FURTHEST EAST WITH THIS SCENARIO AND POTENTIALLY CLOSE ENOUGH FOR A LITTLE SNOW IN THE FAR WEST BY MONDAY NIGHT. KEEPING A DRY FORECAST FOR NOW BUT IT'S WORTH WATCHING. ON TUESDAY...ANOTHER SHORTWAVE WILL LIKELY DROP INTO MONTANA BUT IT MAY STAY NORTH AND EAST OF THE AREA. FLOW GETS MORE AND MORE COMPLEX/CHAOTIC BY THE MIDDLE OF NEXT WEEK WITH MULTIPLE SHORTWAVES DROPPING S AND SEWD DOWN THE FRONT SIDE OF THE WEST COAST RIDGE. FOR NOW WILL KEEP JUST SOME LOW GRADE POPS IN THE MOUNTAINS AND FAR WEST ON WEDNESDAY BUT IT'S QUITE LIKELY ONE OF THESE SHORTWAVES WILL RESULT IN A PERIOD OF SNOW FOR AT LEAST THE MTNS/WEST AND POSSIBLY A LITTLE ELSEWHERE. A COLD...CYCLONIC N-NE FLOW WILL CONTINUE THROUGH THU. ALL OF THIS COMPLEXITY HAS MADE FORECAST LOW AND HIGH TEMPS QUITE THE CHALLENGE THROUGH THE PERIOD WITH INITIAL STEEP INVERSIONS THEN COLD MID LEVELS RETURNING TUESDAY ONWARD. THE ECMWF IS THE COLDEST OF MODELS WITH MORE ENERGY CUTTING THROUGH THE AREA ON WEDNESDAY. EITHER WAY...A COLD PERIOD WITH TRAPPED BASIN AND VALLEYS SLOW TO RECOVER ONCE THIS COLD AIR SETTLES IN BEHIND OUR CHRISTMAS SYSTEM. GENERALLY STICKING WITH 10 TO 20 BELOW ZERO OUT WEST SUNDAY NIGHT AND ZERO TO 10 BELOW CENTRAL BASINS WITH HIGHS MONDAY AND TUESDAY GENERALLY SINGLE DIGITS AND SOME TEENS WEST WITH MAINLY TEENS TO NEAR 20 CENTRAL BASINS. SOME MODERATION MONDAY TO POSSIBLY AROUND FREEZING IN THE FOOTHILL LOCATIONS OF CENTRAL WYOMING AND THE ERN ZONES. TEMPERATURE VARIATIONS WILL TREND SMALLER BY MIDWEEK AS COLDER AIR ALOFT MOVES IN LOWERING HIGHS IN THE WARMER LOCALES AND WITH INCREASED CLOUD COVER AT TIMES...SOMEWHAT LESS BITTER COLD AIR FOR THE TRAPPED BASINS/VALLEYS. BOTTOM LINE...A RATHER COLD LATE DECEMBER PERIOD FOR THE BASINS/VALLEYS WITH ONLY BRIEF MODERATION FOR THE LEE OF THE CENTRAL MTNS/ERN ZONES EARLY NEXT WEEK BEFORE TEMPS FALL THERE ONCE AGAIN. && .AVIATION.../18Z ISSUANCE/ WEST OF THE CONTINENTAL DIVIDE...KBPI/KJAC/KPNA/KRKS ROUTES MVFR CONDITIONS WILL PREVAIL FROM YELLOWSTONE NATIONAL PARK SOUTH TO AFTON AND EAST INTO THE UPPER GREEN RIVER BASIN AND FOOTHILLS DUE TO LOW CIGS AND OCNL LIGHT SNOW. KJAC...KPNA...AND KBPI AIRPORTS WILL BE IMPACTED MOST BY THESE CONDITIONS THROUGH THIS EVENING. SNOW WILL OCCUR AT TIMES OVER THE WESTERN MOUNTAINS THROUGH TONIGHT WITH SOME MOUNTAIN OBSCURATION EXPECTED. KRKS WILL HAVE VFR MAINLY CONDITIONS PREVAILING THROUGH 12Z FRIDAY. EAST OF THE CONTINENTAL DIVIDE...KCOD/KCPR/KLND/KRIW/KWRL ROUTES VFR CONDITIONS WILL PREVAIL THROUGH THE FORECAST PERIOD. GUSTY SOUTHWEST WIND AT KCPR TODAY...DECREASING AROUND 23Z THIS AFTERNOON. THERE WILL BE SOME SNOW OVER THE HIGHER MOUNTAIN PEAKS ALONG THE CONTINENTAL DIVIDE THROUGH TONIGHT WITH MOUNTAIN PEAK OBSCURATION. && .FIRE WEATHER... PERIODS OF SNOWFALL WILL CONTINUE IN THE FAR WEST THROUGH FRIDAY ALONG WITH A BROAD AREA OF SNOWFALL GETTING UNDER WAY ACROSS SOUTHERN...CENTRAL AND EASTERN WYOMING FRIDAY AND FRIDAY EVENING. RELATIVE HUMIDITY WILL BE FAVORABLE TO ELEVATED AS TEMPERATURES CONTINUE A GRADUAL COOLING TREND. MIXING HEIGHTS WILL BE LOW WITH POOR SMOKE DISPERSAL. SATURDAY IS SHAPING UP TO BE A SNOW FREE DAY. A STRONG TEMPERATURE INVERSION AND VERY STABLE CONDITIONS ARE EXPECTED BY SUNDAY MORNING. && .RIW WATCHES/WARNINGS/ADVISORIES... NONE. && SHORT TERM...LIPSON LONG TERM...SKRBAC AVIATION...BRAUN FIRE WEATHER...LIPSON
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE RIVERTON WY 351 AM MST THU DEC 24 2015 WYZ001>020-022>030-251300- YELLOWSTONE NATIONAL PARK-ABSAROKA MOUNTAINS-CODY FOOTHILLS- NORTH BIG HORN BASIN-SOUTHWEST BIG HORN BASIN- SOUTHEAST BIG HORN BASIN-OWL CREEK AND BRIDGER MOUNTAINS- BIGHORN MOUNTAINS WEST-BIGHORN MOUNTAINS SOUTHEAST- NORTHEAST JOHNSON COUNTY-SOUTHEAST JOHNSON COUNTY- TETON AND GROS VENTRE MOUNTAINS-JACKSON HOLE- WIND RIVER MOUNTAINS WEST-WIND RIVER MOUNTAINS EAST- UPPER WIND RIVER BASIN-WIND RIVER BASIN-LANDER FOOTHILLS- GREEN MOUNTAINS AND RATTLESNAKE RANGE- NATRONA COUNTY LOWER ELEVATIONS-CASPER MOUNTAIN-STAR VALLEY- SALT RIVER AND WYOMING RANGES-UPPER GREEN RIVER BASIN FOOTHILLS- UPPER GREEN RIVER BASIN-SOUTH LINCOLN COUNTY- ROCK SPRINGS AND GREEN RIVER-FLAMING GORGE-EAST SWEETWATER COUNTY- 351 AM MST THU DEC 24 2015 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF WY...CENTRAL WYOMING...NORTH CENTRAL WYOMING...NORTHWEST WYOMING...SOUTH CENTRAL WYOMING...SOUTHWEST WYOMING AND WEST CENTRAL WYOMING. .DAY ONE...TODAY AND TONIGHT .LIGHT TO MODERATE SNOW EXPECTED TO CONTINUE ACROSS THE WEST ONCE AGAIN TODAY. .DAYS TWO THROUGH SEVEN...CHRISTMAS DAY THROUGH WEDNESDAY CHRISTMAS DAY...SNOW DEVELOPING OVER MUCH OF CENTRAL AND SOUTHERN WYOMING. SUNDAY AND MONDAY...MORNING FOG MAY DEVELOP OVER THE BASINS AND VALLEYS OF CENTRAL AND WESTERN WYOMING. IT WILL ALSO BE BITTER COLD WITH MORNING LOWS OF 5 TO 15 BELOW IN THE CENTRAL BASINS AND 15 TO 25 BELOW WEST OF THE DIVIDE. .SPOTTER INFORMATION STATEMENT... SPOTTERS ARE ENCOURAGED TO REPORT SNOWFALL AMOUNTS FROM YESTERDAY AS WELL AS ANY NEW SNOWFALL AMOUNTS THAT OCCUR TODAY. THANK YOU. TEAM RIVERTON
The national radar mosaic for the moment the first event began.
1 avalanche. Local standard time, as filed.
An avalanche on Teton Pass buried two snowmobilers under up to five feet of snow. One of the skiers suffered a broken leg.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Wyoming in 2015Every state in 2015This day in weather historyWarnings in Wyoming, December 2015
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: 605831.