A moist Pacific storm moved into Wyoming and brought heavy snow to areas west of the Continental Divide. The heaviest snow fell in the Salt and Wyoming ranges where many areas received over a foot of new snow.
Every event with a place to put it; 10 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 moist Pacific storm moved into Wyoming and brought heavy snow to areas west of the Continental Divide. The heaviest snow fell in the Salt and Wyoming ranges where many areas received over a foot of new snow. The maximum amount was 26 inches estimated at the Spring Creek Divide SNOTEL. Amounts over a foot also fell in the Tetons, Yellowstone National Park, and the Absaroka Range. The western valleys generally received between 6 and 10 inches of snow.
East of the Continental Divide, the same storm system produced strong winds near Clark and across eastern Sweetwater and southern Fremont counties. A tight pressure gradient and strong low level winds mixed to the ground to create the high winds. Peak speeds were registered near the foothills around Clark where a maximum gust of 92 mph was recorded. Portions of Fremont and Sweetwater counties saw wind gusts of 60 to 69 mph.
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 20, 3:13 AM MST, 6 hours 47 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RIVERTON WY 313 AM MST SAT DEC 20 2014 .SHORT TERM...TODAY THROUGH MONDAY NIGHT AN INTERESTING FORECAST PERIOD WITH A LOT OF POTENTIALLY SIGNIFICANT WEATHER DEVELOPING. A NEARLY ZONAL FLOW PATTERN IS EXPECTED THIS MORNING AND AFTERNOON...WITH SOME MOISTURE INCREASE SNOWFALL COVERAGE A BIT ACROSS WESTERN WYOMING. A PACIFIC STORM SYSTEM WILL CONTINUE TO MOVE THROUGH THE INTERMOUNTAIN WEST SATURDAY EVENING...WITH SNOWFALL INCREASING ACROSS WESTERN WYOMING. ADDITIONALLY...AN INCREASED TEMPERATURE GRADIENT IS EXPECTED BETWEEN CODY AND THE EASTERN PORTION OF YELLOWSTONE NATIONAL PARK. ADDITIONAL MOUNTAIN WAVE SIGNATURES ARE BEING DEMONSTRATED IN CURRENT MODEL ANALYSIS...WITH VERY STRONG WIND POSSIBLE AROUND THE FAVORED CLARK AREA. A HIGH WIND WATCH IS IN EFFECT FOR THIS LOCATION. SNOWFALL IS EXPECTED TO INCREASE TONIGHT AND PERSIST THROUGH MONDAY MORNING. SNOWFALL IS LOOKING TO BECOME HEAVY AT TIMES WITH SIGNIFICANT ACCUMULATIONS POSSIBLE ACROSS THE WESTERN MOUNTAINS AND VALLEYS. THE WINTER STORM WATCH REMAINS ACROSS THE AREA. ADDITIONAL LOCATIONS LOOK FAVORABLE FOR THE NEED OF WINTER WEATHER ADVISORIES...AND SNOWFALL TOTALS SHOULD BE ABLE TO BE FINALIZED DURING THE UPCOMING SHIFT. SIMULTANEOUSLY...MODELS CONTINUE TO INDICATE THE POTENTIAL FOR VERY STRONG WINDS ACROSS SWEETWATER COUNTY AND INTO THE GREEN MOUNTAINS AND RATTLESNAKE RANGE SUNDAY AFTERNOON AND EVENING. ANOTHER HIGH WIND WATCH HAS BEEN ISSUED TO ACCOUNT FOR THESE POTENTIALLY STRONG WINDS. SNOWFALL AND WIND IS EXPECTED TO WEAKEN MONDAY AS NORTHWEST FLOW WORKS TO BUILD OVER THE AREA...WITH MOST ACTIVITY WANED BY MONDAY AFTERNOON. SOME LIGHT SNOWFALL WILL REMAIN POSSIBLE ACROSS AREAS EAST OF THE DIVIDE LATE MONDAY AS THE SYSTEM CONTINUES TO MOVE INTO THE CENTRAL PLAINS. .LONG TERM...TUESDAY THROUGH SATURDAY QUITE THE MODEL DIVERGENCE TONIGHT BETWEEN THE GFS AND THE ECMWF. THE MODELS START OUT PRETTY CLOSE THROUGH TUESDAY WITH TRANSITORY RIDGE MOVING ACROSS THE AREA AFTER OUR SUN/MON SNOW AND WIND EVENT. ECMWF HAS SOME MOISTURE AND UPGLIDE IN THE PATTERN ALREADY TUESDAY SO SOME CHANCE POPS REMAIN...ESPECIALLY BY TUESDAY NIGHT. AFTER THAT...THE CHANGES BECOME VERY SIGNIFICANT. THE 00Z GFS ALLOWS THE CHRISTMAS EVE/CHRISTMAS DAY SYSTEM TO COME IN AT A HIGHER LATITUDE WITH LESS RIDGING BEHIND IT. THIS SOLUTION HAS A SEWD MOVING DISTURBANCE COMING THROUGH WITH THE MAIN EFFECT BEING STRONG TO HIGH WIND ACROSS THE LOWER ELEVATIONS AND A QUICK SHOT OF SNOW...MAINLY IN THE MOUNTAINS. THE ECMWF ON THE OTHER HAND IS STILL SHOWING THIS SYSTEM DROPPING INTO THE PACNW AND THEN THE NRN GREAT BASIN AS RIDGING DEVELOPS QUICKLY BEHIND IT. THE SYSTEM THEN CLOSES OFF OVER SRN WYOMING ON CHRISTMAS DAY WITH WIDESPREAD SNOW SPREADING EWD AND SWD CHRISTMAS EVE INTO EARLY CHRISTMAS DAY. THE DEVELOPMENT OF THIS SYSTEM IS STILL A COMBINATION OF THE CURRENT TROUGH OVER THE CENTRAL PACIFIC ACCOMPANIED BY AT LEAST A 170-180KT JET AND A POCKET OF COLD AIR POURING SOUTH IN THE KAMCHATKA REGION. A STRONG TROUGH WITH VERY COLD AIR BEHIND THIS SYSTEM AND A LEAD DISTURBANCE ARE RESPONSIBLE FOR THE UPSTREAM RIDGE ALONG THE COAST THAT THE ECMWF ESPECIALLY SHOWS. THE GFS HAS A SIMILAR SCENARIO BUT DIVERGES SLIGHTLY NOT ALLOWING THE RIDGE TO BUILD UPSTREAM AS MUCH. THAT MAKES ALL THE DIFFERENCE IN THE WORLD FOR OUR SENSIBLE WEATHER. STICKING CLOSER TO THE MORE CONSISTENT ECMWF AND USUALLY BETTER EURO IN THIS SCENARIO WHICH MEANS LITTLE CHANGE FOR OUR GOING FORECAST. COLD BEHIND THIS SYSTEM...ESPECIALLY WITH THE ECMWF SOLUTION FRIDAY NIGHT. ANOTHER POTENTIAL SEWD COLD MOVING SHORTWAVE MAY MOVE INTO THE NWRN PARTS AT THE END OF THIS PERIOD. THIS SYSTEM IS ACTUALLY THE ONE EXPECTED TO PUMP SOME WARM AIR INTO OUR RIDGE ALONG THE COAST AND AID IN THE DIGGING OUR CHRISTMAS SYSTEM. && .AVIATION.../12Z ISSUANCE/ INCREASING MOISTURE PER MODELS INTO WESTERN WYOMING ON SATURDAY. SNOW WILL INCREASE AND BECOME MODERATE TO HEAVY BY SATURDAY NIGHT...ESPECIALLY IN THE MOUNTAINS AND POSSIBLY NEAR KJAC. THIS WILL RESULT IN MOUNTAIN OBSCURATION FOR ALL MOUNTAIN RANGES. OUTSIDE OF THE WIND RIVER BASIN OF CENTRAL WYOMING...VFR CONDITIONS CAN BE EXPECTED THROUGH SATURDAY EAST OF THE DIVIDE. WITH A TIGHTENING PRESSURE GRADIENT WINDS WILL INCREASE SATURDAY...ESPECIALLY ACROSS THE SOUTHWESTERN WIND CORRIDOR FROM KRKS TO KCPR. ANY FOG AT KLND AND KRIW SHOULD BEGIN TO LEFT AROUND 15 TO 16Z AND BE FULLY LIFTED BY 19Z. && .FIRE WEATHER... A PLETHORA OF POTENTIALLY ADVERSE WEATHER CONDITIONS ARE POSSIBLE OVER THE NEXT COUPLE DAYS. STRONG WIND MAY DEVELOP ACROSS THE CODY FOOTHILLS LATE THIS EVENING...AND CONTINUE INTO SUNDAY MORNING. MEANWHILE...SNOWFALL WILL INTENSIFY ACROSS THE WESTERN MOUNTAINS AND VALLEYS...AND WILL PERSIST THROUGH MONDAY MORNING. SNOWFALL MAY COMBINE WITH GUSTY WIND AT TIMES. AS THE SYSTEM CONTINUES TO IMPACT THE STATE...STRONG WIND IS POSSIBLE TO DEVELOP ACROSS GREEN MOUNTAIN AND RATTLESNAKE RANGE...ALONG WITH THE INTERSTATE 80 CORRIDOR THROUGH SWEETWATER COUNTY. THESE STRONG WINDS AND COMBINED SNOW AND WIND WILL MAKE FOR GENERALLY UNFAVORABLE BURN CONDITIONS. && .RIW WATCHES/WARNINGS/ADVISORIES... HIGH WIND WATCH FROM SUNDAY MORNING THROUGH SUNDAY EVENING WYZ019-028>030. WINTER STORM WATCH FROM THIS EVENING THROUGH MONDAY MORNING WYZ002-014-015-025. WINTER STORM WATCH FROM THIS EVENING THROUGH MONDAY MORNING WYZ001-012-013-023-024. HIGH WIND WATCH FROM THIS EVENING THROUGH SUNDAY MORNING WYZ003. && SHORT TERM...BRANHAM LONG TERM...SKRBAC AVIATION...HATTINGS FIRE WEATHER...BRANHAM
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE RIVERTON WY 328 AM MST SAT DEC 20 2014 WYZ001>020-022>030-211200- 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- 328 AM MST SAT DEC 20 2014 ...WINTER STORM WATCH FOR PORTIONS OF WESTERN WYOMING THIS EVENING THROUGH MONDAY MORNING... ...HIGH WIND WATCH FOR THE CODY FOOTHILLS TONIGHT THROUGH 11 AM SUNDAY... ...HIGH WIND WATCH SOUTHERN WYOMING SUNDAY AFTERNOON AND EVENING... THIS HAZARDOUS WEATHER OUTLOOK IS FOR WESTERN AND CENTRAL WYOMING. .DAY ONE...TODAY AND TONIGHT PATCHY FOG IS POSSIBLE IN THE LOW LYING AROUND THE WIND RIVER BASIN AND LANDER FOOTHILLS THIS MORNING...WHICH SHOULD LIFT BY THE LATE MORNING HOURS. STRONG WIND IS POSSIBLE ACROSS THE CODY FOOTHILLS TONIGHT...WITH GUSTS UP TO 60 MPH POSSIBLE AROUND THE CLARK AREA. PLEASE SEE THE HIGH WIND WATCH PRODUCT FOR ADDITIONAL DETAILS. ADDITIONALLY... SNOWFALL ACROSS WESTERN WYOMING MAY INTENSIFY DURING THE EVENING HOURS AND CONTINUE THROUGH THE OVERNIGHT HOURS. .DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY SUNDAY THROUGH MONDAY...SIGNIFICANT SNOWFALL AND WIND EXPECTED IN WESTERN WYOMING. SNOWFALL AMOUNTS OF 1 TO 2 FEET ARE POSSIBLE IN THE WESTERN MOUNTAINS WITH THE LOWER ELEVATIONS AND VALLEYS POTENTIALLY RECEIVING 5 TO 10 INCHES WITH LOCALLY HIGHER AMOUNTS. VERY STRONG WINDS ARE EXPECTED ACROSS SWEETWATER COUNTY AND INTO THE GREEN MOUNTAINS/RATTLESNAKE RANGE SUNDAY INTO MONDAY. STRONG WINDS MAY ALSO BLOW SUNDAY NIGHT FROM DUBOIS TO RIVERTON. WEDNESDAY NIGHT THROUGH CHRISTMAS DAY...A NEW STORM SYSTEM WILL DEVELOP TO OUR WEST SPREADING SNOW FROM WEST TO EAST. THE POTENTIAL FOR SIGNIFICANT SNOWFALL IS STILL A POSSIBILITY ACROSS CENTRAL AND SOUTHWEST WYOMING ON CHRISTMAS DAY. COMPUTER MODELS HAVE DIVERGED MORE TONIGHT SO STAY TUNED OVER THE NEXT SEVERAL DAYS ON THIS POTENTIAL TRAVEL IMPACTING STORM. .SPOTTER INFORMATION STATEMENT... SPOTTERS ARE ENCOURAGED TO STRONG WINDS IN THE CODY FOOTHILLS TONIGHT AND SNOWFALL IN THE FAR WEST. THANK YOU. TEAM RIVERTON
The national radar mosaic for the moment the first event began.
7 winter storm, 3 high wind. Local standard time, as filed.
Heavy snow fell in the Tetons. At the Jackson Hole Ski Resort, 15 inches fell on the summit. The highest amount was 16 inches the Grassy Lake SNOTEL.
The Wolverine SNOTEL estimated 12 inches of new snow.
Snowfall totals across the Star Valley ranged from 10 inches at Thayne to 5 inches at Afton where the snow mixed with rain at times.
Heavy snow fell across the Salt and Wyoming ranges with many areas seeing over 1 foot of new snow. The highest amount was 26 inches at the Spring Creek Divide SNOTEL site.
Heavy snow fell across portions of Yellowstone National Park. The highest total was 19 inches at the Lewis Lake Divide SNOTEL.
Snow amounts across the Jackson Valley ranged from 8.3 inches at Moose to 2 inches in the town of Jackson.
The RAWS site at Camp Creek had a maximum wind gust of 69 mph.
Snowfall amounts across the Upper Green River Basin Foothills ranged from 5 to 8.5 inches. The highest amounts fell north and west of Daniel.
Many wind gusts past 58 mph were recorded at the weather sensor 5 miles WNW of Clark. The maximum wind gusts were 91 and 92 mph between 0330 and 0430MST.
Several sites in eastern Sweetwater County had wind gusts past 58 mph. The highest gust of 67 mph occurred at Snow Springs. The ASOS at Rock Springs-Sweetwater County Airport clocked a gust to 59 mph.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Wyoming in 2014Every state in 2014This day in weather historyWarnings in Wyoming, December 2014
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: 549090, 549094, 549087, 549088, 549093, 549092, 549085, 549095, 549084, 549086.