Snow spread north across the Interstate 80 corridor and into central Wyoming during the afternoon of Monday, March 2. The snow came down hard in Casper and other sections of Natrona County late in the afternoon, with accumulations quickly piling up.
Every event with a place to put it; 5 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.
Snow spread north across the Interstate 80 corridor and into central Wyoming during the afternoon of Monday, March 2. The snow came down hard in Casper and other sections of Natrona County late in the afternoon, with accumulations quickly piling up. Cold air behind a cold front arrived later in the evening causing road conditions to rapidly deteriorate. The snow became more widespread Monday evening and continued into the morning hours of Tuesday, March 3. The combination of snow and cold caused the closure of Interstate 80 and other state and US highways across southern and central Wyoming. The snow dwindled Tuesday morning and roads were re-opened. Total snowfall was 12 to 18 inches on Casper Mountain, 6 to 9 inches around Casper, Lander, and Ft. Washakie, and 3 to 5 inches at many other locations in central and southern Wyoming.
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 Mar 2, 2:36 AM MST, 7 hours 24 minutes earlier.
AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE RIVERTON WY 236 AM MST MON MAR 2 2015 .SHORT TERM...TODAY THROUGH WEDNESDAY NIGHT FORECAST STILL ON TRACK FOR THE UPCOMING STORM SYSTEM TO IMPACT THE AREA THROUGH TUESDAY EVENING. PRECIPITATION WILL BEGIN ACROSS SOUTHERN SWEETWATER COUNTY THIS MORNING AND AFTERNOON...BUT TEMPERATURES WILL BE TOO MILD TO PRODUCE MUCH IN THE WAY OF HAZARDOUS CONDITIONS. A CANADIAN COLD FRONT AND ASSOCIATED SNOWFALL WILL IMPACT NORTHERN WYOMING THIS EVENING WITH PERIODS OF MODERATE SNOWFALL...STRONG WIND...AND MUCH COLDER TEMPERATURES. THIS SYSTEM WILL QUICKLY MOVE SOUTH THROUGH THE FORECAST AREA THROUGH THE EVENING HOURS. THE SYSTEM WILL COMBINE WITH THE ALREADY OCCURRING PRECIPITATION ACROSS SWEETWATER...SOUTHEASTERN FREMONT...AND NATRONA COUNTIES TO CREATE WINTER STORM CONDITIONS WITH PERIODS OF HEAVY SNOWFALL AND GUSTY WIND. WINTER STORM WARNINGS HAVE BEEN ISSUED FOR THESE AREAS FOR THIS EVENING THROUGH WEDNESDAY AFTERNOON. GENERAL BELIEF IS THAT THE FLOW IS NOT QUITE IDEAL FOR THE INCLUSION OF THE LANDER FOOTHILLS IN THE WINTER STORM WARNING. THEIR EXPECTED SNOWFALL AMOUNTS HAVE LEFT THEM TO BE INCLUDED IN THE WINTER WEATHER ADVISORY...THOUGH IT IS POSSIBLE SOME AREAS IN THE LANDER FOOTHILLS MAY VERY WELL SEE HIGHER AMOUNTS OF SNOWFALL. ALSO DECIDED TO INCLUDE THE WESTERN SLOPES OF THE WIND RIVER MOUNTAINS IN THE ADVISORY TO COVER THE FULL LENGTH OF HIGHWAY 28 THROUGH SOUTH PASS WHERE WIND AND SNOWFALL WILL RESULT IN HAZARDOUS TRAVEL CONDITIONS OVERNIGHT. SNOWFALL STILL LOOKS TO TAPER OFF QUICKLY TUESDAY NIGHT WITH BUILDING NORTHERLY FLOW. GENERALLY DRY CONDITIONS ANTICIPATED BY LATE WEDNESDAY MORNING ACROSS THE FORECAST AREA. THE COLDER TEMPERATURES ASSOCIATED WITH THIS SYSTEM WILL LINGER THROUGH WEDNESDAY...WITH SINGLE DIGITS EXPECTED WEDNESDAY NIGHT. .LONG TERM...THURSDAY THROUGH MONDAY A RELATIVELY DRY NORTHWEST FLOW...AND A WARMING TREND TO SEASONAL LEVELS WILL OCCUR LATE THIS WEEK...AND REMAIN IN PLACE THROUGH EARLY NEXT WEEK. THE MAIN CAVEAT IS THE ECMWF STILL SHOWS A DISTINCT SHORTWAVE TROUGH...AND ASSOCIATED WEAK COLD FRONT PUSHING SOUTHEAST ACROSS THE AREA IN THE FRIDAY/SATURDAY TIME FRAME. HOWEVER...THE 00Z GFS AND GEM ARE KEEPING THIS WAVE LESS AMPLIFIED AND FARTHER NORTHEAST. WILL HAVE SOME SLIGHT MOUNTAIN POPS FOR THIS SYSTEM FRIDAY AND SATURDAY...BUT IF MODELS TREND TOWARD THE ECMWF...POPS WILL NEED TO BE EXPANDED AND INCREASED...MAINLY FRIDAY NIGHT/SATURDAY. && .AVIATION.../18Z ISSUANCE/ EAST OF THE DIVIDE...KCOD/KCPR/KLND/KRIW/KWRL ROUTES AN EXPANSIVE AREA OF SNOWFALL WILL PERSIST ACROSS THE EAST HALF OF SWEETWATER COUNTY THROUGH 00Z TODAY RESULTING IN WIDESPREAD IFR/MVFR CONDITIONS AND MTN OBSCURATIONS. VFR CONDITIONS...FL SCT-BKN200-250 WILL CONTINUE NORTH AND WEST OF THERE THROUGH 21Z THIS AFTERNOON. A LOW PRESSURE SYSTEM LIFTING NE ACROSS THE GREAT BASIN WILL PUSH SCT MVFR -SHRASN NORTH TO A VCNTY KLND-KCPR LINE 21Z TODAY-00Z TUE. CONDITIONS WILL THEN DETERIORATE RAPIDLY AFTER 00Z TUE AS A COLD FRONT PUSHES DOWN FROM THE NORTH BRINGING WIDESPREAD MVFR/IFR -SN AND MTN OBSCURATIONS ACROSS THE AREA BY 4Z TUE ALONG WITH INCREASING NORTH WIND AND SOME BLOWING SNOW. THE HEAVIEST SNOWFALL AND AREAS OF LIFR CONDITIONS WILL BE FOUND VCNTY AND SOUTH OF A KCPR-KLND LINE AS THE SNOWFALL AND LOW CIGS ALREADY IN PLACE ACROSS THE EAST HALF OF SWEETWATER COUNTY CONTINUE TO INCREASE AND LOWER RESPECTIVELY. THESE CONDITIONS WILL PERSIST THROUGH 12Z TUE. THESE CONDITIONS WILL BEGIN TO IMPROVE FROM NORTHWEST TO SOUTHEAST AFTER 12Z TUESDAY. WEST OF THE DIVIDE...KBPI/KJAC/KPNA/KRKS ROUTES THE UPPER LEVEL DISTURBANCE BRINGING AN INITIAL BAND OF MVFR/IFR -SN NORTH INTO SOUTHERN WYOMING TO VCNTY AND SOUTH OF INTERSTATE 80 WILL IMPROVEMENT SOMEWHAT BY 19Z THIS AFTERNOON. THEN MORE WIDESPREAD PERSISTENT IFR SNOW IS EXPECTED TO DEVELOP ACROSS SOUTHERN WYOMING AROUND 20Z TODAY AND PERSIST INTO THE OVERNIGHT HOURS. A CANADIAN COLD FRONT PUSHING DOWN FROM THE NORTH WILL SPREAD SNOW SOUTH ALONG THE DIVIDE THIS EVENING...FILLING WESTERN WYOMING WITH WIDESPREAD MVFR/IFR -SN BY 06Z TUES ALONG WITH MTNS BECOMING MOSTLY OBSCURED. KRKS WILL BE IN THE BATTLE ZONE BETWEEN THE NORTHEAST AND WEST WINDS FOR MUCH OF TUESDAY WITH WEST WINDS WEST OF THERE AND NORTHEAST WINDS NORTH AND EAST OF THERE. THE SNOWFALL AND CIGS WILL DECREASE AND LIFT RESPECTIVELY FROM NORTHWEST TO SOUTHEAST DURING THE DAY TUESDAY. && .FIRE WEATHER... A WINTRY STORM SYSTEM IS STILL ON TRACK TO IMPACT THE FORECAST AREA THIS EVENING AND THROUGH WEDNESDAY MORNING. MUCH OF THE AREA IS ANTICIPATED TO EXPERIENCE LIGHT TO MODERATE SNOWFALL AMOUNTS...WITH AREAS OF SOUTHWESTERN WYOMING EXPECTED TO SEE ENHANCED SNOWFALL. IN ADDITION TO SNOWFALL...THE APPROACHING CANADIAN COLD FRONT WILL BRING MUCH COLDER TEMPERATURES...AND PERIODS OF VERY STRONG WIND THROUGH THE OVERNIGHT HOURS. && .RIW WATCHES/WARNINGS/ADVISORIES... WINTER STORM WARNING FROM 6 PM THIS EVENING TO 6 PM MST TUESDAY WYZ019-020-022-030. WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 6 PM MST TUESDAY WYZ002>011-014>018-028-029. && SHORT TERM...BRANHAM LONG TERM...WM AVIATION...LIPSON FIRE WEATHER...BRANHAM
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE RIVERTON WY 300 AM MST MON MAR 2 2015 WYZ001>020-022>030-031300- 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- 300 AM MST MON MAR 2 2015 ...WINTER WEATHER ADVISORIES AND WINTER STORM WARNINGS IN EFFECT FOR AREAS EAST OF THE DIVIDE AND SWEETWATER COUNTY TONIGHT AND TUESDAY... THIS HAZARDOUS WEATHER OUTLOOK IS FOR WESTERN AND CENTRAL WYOMING. .DAY ONE...TODAY AND TONIGHT SNOWFALL WILL BEGIN ACROSS SOUTHERN WYOMING THIS AFTERNOON AS A WEAK SYSTEM MOVES UP FROM COLORADO. MEANWHILE...A STRONGER SYSTEM WILL MOVE INTO NORTHERN WYOMING THIS EVENING AND WILL QUICKLY SPREAD SNOWFALL ACROSS MUCH OF WESTERN AND CENTRAL WYOMING. STRONG WIND AND MUCH COLDER TEMPERATURES WILL ALSO ACCOMPANY THIS SYSTEM. SIGNIFICANT SNOWFALL IS EXPECTED...ESPECIALLY ACROSS SWEETWATER...SOUTHEASTERN FREMONT...AND NATRONA COUNTIES. ADDITIONAL AREAS OF CENTRAL AND NORTHERN WYOMING WILL ALSO SEE NOTABLE IMPACTS FROM THIS SYSTEM. SNOWFALL AND WIND WILL CONTINUE THROUGH TUESDAY AFTERNOON BEFORE WEAKENING. .DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY TUESDAY...SIGNIFICANT SNOW AND BLOWING SNOW IS ANTICIPATED OVER MUCH OF THE AREA EAST OF THE DIVIDE...AND ACROSS SWEETWATER COUNTY. SNOWFALL WILL CONTINUE THROUGH THE AFTERNOON HOURS BEFORE WEAKENING DURING THE EVENING. TUESDAY NIGHT AND WEDNESDAY...BITTER COLD TEMPERATURES EXPECTED AND PERIODS OF GUSTY WIND COULD RESULT IN FRIGID WIND CHILLS. .SPOTTER INFORMATION STATEMENT... SPOTTERS ARE ENCOURAGED TO REPORT SNOWFALL AMOUNTS AND STRONG WIND OVER 40 MPH. THANK YOU. TEAM RIVERTON
The national radar mosaic for the moment the first event began.
5 winter storm. Local standard time, as filed.
A rural ranch in northeast Sweetwater County received about one foot of snow.
An NWS employee reported 6 inches at Sand Draw southeast of Riverton.
Snowfall totals topped one foot on Casper Mountain.
Snowfall of 6.2 inches was reported about 4 miles southwest of Casper.
Lander reported 6 inches of snow at 0500MST.
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, March 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: 556412, 556408, 556410, 556409, 556407.