A cold front dropped south across Wyoming and brought snow and wind to portions of the area. The worst conditions were across northern Johnson County where strong northwest wind gusts topped 40 mph for about 15 hours and peak gusts exceeded 60 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 cold front dropped south across Wyoming and brought snow and wind to portions of the area. The worst conditions were across northern Johnson County where strong northwest wind gusts topped 40 mph for about 15 hours and peak gusts exceeded 60 mph. The combination of strong wind and snow brought near whiteout conditions and temperatures fell from the upper 20s to the teens. This caused several accidents on interstates 25 and 90 near Buffalo and prompted the closure of these roads on the afternoon of Wednesday, February 25.
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 25, 3:28 AM MST, 3 hours 2 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RIVERTON WY 328 AM MST WED FEB 25 2015 .SHORT TERM...TODAY THROUGH FRIDAY NIGHT THE COLD FRONT APPEARS TO HAVE SLIPPED SOUTH ACROSS NORTHERN JOHNSON COUNTY WHERE NORTH WINDS ARE NOW GUSTING TO 30 KNOTS AT BYG. BILLINGS RADAR IS SHOWING STRATIFORM PRECIP FALLING BEHIND THE FRONT...MOSTLY VIRGA ATTM. THIS PRECIP...WHICH WILL START AS RAIN AT THE LOWER ELEVATIONS BEFORE TURING TO SNOW AND WILL SPREAD SOUTH ACROSS JOHNSON AND NATRONA COUNTIES DURING THE REMAINDER OF THE PRE DAWN HOURS AND WILL LIKELY REACH THE DIVIDE BY 12Z THIS MORNING. THE TROUGH RESPONSIBLE FOR PUSHING THE FRONTAL BOUNDARY SOUTH WILL BE FAIRLY CONVOLUTED AND WILL COME THROUGH IN ABOUT 4 SEPARATE PIECES OF ENERGY TODAY THROUGH TONIGHT FROM THE NW. DYNAMICS WITH THIS SYSTEM ARE NOT VERY IMPRESSIVE BUT MOST AREAS OF THE CWA WILL SEE SNOWFALL IN ONE FORM OR ANOTHER WITH THE BEST CHANCES EAST OF THE DIVIDE AND THE LEAST LIKELY AREAS OVER SOUTHWEST WY. LIFTED INDICES HAVE BEEN PROGGED TO RANGE FROM ZERO TO -2 OVER THE WESTERN CWA FOR THIS AFTERNOON WITH THE LAST FEW RUNS SO A LIGHTNING STRIKE OF TWO COULD OCCUR RIGHT ALONG THE DIVIDE WHERE THE BEST MOISTURE AND INSTABILITY COULD OVERLAP JUST AHEAD OF THE FRONT AS COLD AIR POURS IN ALOFT BUT WILL LEAVE OUT OF THE GRIDS. KEPT SUB ADVISORY OR LOW END ADVISORY FOR SNOW AMOUNTS MOST AREAS ALONG AND EAST OF THE DIVIDE TODAY THROUGH TONIGHT ALTHOUGH THERE WILL LIKELY BE LOCALLY HIGHER AMOUNTS UNDERNEATH HEAVIER SNOW BANDS. DECIDED TO ISSUE A WINTER WEATHER ADVISORY VALID FROM 09Z THIS MORNING THROUGH 07Z THU AS INCREASING NORTH WIND WILL COMBINE WITH THE SNOWFALL TO PRODUCE MORE OF AN IMPACT IN THOSE AREAS. THIS WILL BLEND IN WELL WITH BYZ ADVISORIES. THE LOCAL WRF IS ADVERTISING FAIRLY GOOD SNOWBANDING OFF THE BIG HORN MTNS WITH 6 HOUR PRECIP AMOUNTS OF MORE THAN ONE HALF INCH FOR WHAT ITS WORTH. IN FACT...MUCH OF THE SNOWFALL THAT OCCURS TODAY WILL BE IN THE FORM OF BANDING WITH THE COLD AIR ADVECTING IN AT H7 FROM THE NNW. SNOWFALL RATES SHOULD GRADUALLY DECLINE TONIGHT AS H7 TEMPS BECOME COLD ENOUGH FOR LESS FAVORABLE DENDRITIC GROWTH. BY 12Z THURSDAY THE H7 TEMPS WILL DROP TO -23C OVER NE JOHNSON COUNTY. LIGHT SNOW WILL CONTINUE IN WESTERN WYOMING THU AS THE ENERGY WITHIN THE MAIN TROUGH PROPAGATES SOUTHWEST TOWARD THE GREAT BASIN. THEN A TROUGH TRACKING FROM THE PACIFIC NORTHWEST TO THE GREAT BASIN WITHIN THE MAIN TROUGH WILL AMPLIFY THE MAIN TROUGH AND WILL KEEP THE LIGHT SNOW GOING IN PARTS OF THE WEST THURSDAY NIGHT...FRIDAY AND FRIDAY NIGHT. AFTER THE COLDEST OF THE 700MB TEMPERATURES PASS BY...FRIDAY MORNING SHOULD BE THE COLDEST PERIOD OF THE WEEK ALONG WITH SOME BELOW ZERO READINGS AS SKIES CLEAR EAST OF THE DIVIDE AND FRESH SNOW COVER REFRIGERATES THE AIR. .LONG TERM...SATURDAY THROUGH WEDNESDAY SYNOPSIS...A STORM SYSTEM DIGGING INTO THE SOUTHWEST U.S. WILL BRING CHANCES OF SNOW ACROSS THE AREA SATURDAY WITH THE MOST WIDESPREAD COVERAGE EXPECTED ACROSS THE SOUTH AND WEST. COLD CANADIAN SURFACE HIGH PRESSURE AND A DRIER AIRMASS WILL BUILD IN FROM THE NORTH SATURDAY NIGHT AND SUNDAY. MAINLY DRY WEATHER WITH MORE SEASONAL TEMPERATURES ARE EXPECTED ON MONDAY. ANOTHER PACIFIC STORM SYSTEM AND ASSOCIATED CANADIAN COLD FRONT WILL SPREAD CHANCES OF SNOW ACROSS THE AREA ON TUESDAY. DISCUSSION...UPPER RIDGE IS EXPECTED TO REMAIN ACROSS THE EASTERN PACIFIC THROUGH EARLY NEXT WEEK WITH A SERIES OF PACIFIC STORM SYSTEMS CONTINUING TO RIDE OVER THE TOP OF THE RIDGE...ACROSS ALASKA...BEFORE PLUNGING SOUTH ACROSS THE WESTERN U.S. THE NEXT IN THIS SERIES WILL DIVE ACROSS THE NW U.S. ON FRIDAY...WITH AN H5 LOW CLOSING OFF OVER NEVADA ON SATURDAY. LIKE THE LAST FEW SYSTEMS...A SEPARATE CLIPPER IN THE NORTHERN STREAM WILL DRIVE A CANADIAN COLD FRONT SOUTH INTO THE NORTHERN PLAINS WITH THE FRONT BACKING INTO THE EAST SLOPES OF THE DIVIDE ON SATURDAY. THIS WILL RESULT IN ANOTHER SHOT OF VERY COLD AIR WITH AREAS OF UPSLOPE LIGHT 'DRY' SNOW ACROSS CENTRAL WYOMING. THE SOUTHWEST PORTION OF THE STATE WILL STAND THE BETTER CHANCE OF RECEIVING ANYTHING CLOSE TO ADVISORY AMOUNTS. UPPER TROUGH IS EXPECTED TO SHEAR OUT ON SUNDAY WITH DEFORMATION AREA NEAR OUR SOUTH OF INTERSTATE 80 SUNDAY AFTERNOON...WITH ANY PRECIPITATION PUSHING NORTH FROM REMAIN SW LOW NOT MAKING MUCH FURTHER NORTH THAN INTERSTATE 80. SW LOW IS EXPECTED TO GET KICKED OUT BY NEXT SYSTEM DIVING DOWN INTO THE NW U.S. ON MONDAY. WYOMING LOOKS TO BE MAINLY DRY BETWEEN THESE TWO SYSTEMS ON MONDAY. THIS NEXT SYSTEM TAKE A SIMILAR TRACK INTO THE SW U.S. ON TUESDAY AND IS LIKEWISE EXPECTED TO PULL A CANADIAN COLD FRONT AND CHANCES OF SNOW SOUTH ACROSS THE AREA. && .AVIATION.../12Z ISSUANCE/ EAST OF THE DIVIDE...KCOD/KCPR/KLND/KRIW/KWRL ROUTES A COLD FRONT WILL PUSH SOUTH ACROSS THE AREA THIS MORNING. PERIODS OF MVFR/IFR CONDITIONS IN LOW CLOUDS...AS WELL AS A COMBO OF SNOW SHOWERS AND UPSLOPE STRATIFORM SNOW...DEVELOPING MAINLY ALONG AND BEHIND THE COLD FRONT. THESE LOW CLOUDS AND BANDS OF SNOW SHOWERS WILL CONTINUE THROUGH THE EVENING...BECOMING LESS WIDESPREAD AND INTENSE AS THE NIGHT PROGRESSES. HOWEVER...AREAS OF MVFR CEILINGS AND SOME LIGHT SNOW IS EXPECTED THROUGHOUT THE TAF PERIOD. BREEZY TO WINDY NORTHERLY WINDS WILL OCCUR TODAY IN WAKE OF THE COLD FRONT...WITH WINDS WEAKENING TONIGHT. WEST OF THE DIVIDE...KBPI/KJAC/KPNA/KRKS ROUTES A DISTURBANCE SLIDING SOUTH ACROSS THE AREA WILL RESULT IN SOME SNOW SHOWER ACTIVITY...BUT NOT ENOUGH COVERAGE TO PREVAIL ANY LOW CLOUDS OR VSBYS AT THIS TIME. THE ONLY EXCEPTION WILL BE OVER THE SOUTH...WHERE A COLD FRONT WILL SLIDE WEST ACROSS SWEETWATER COUNTY LATE THIS AFTERNOON INTO EARLY EVENING WITH A DECENT CHANCE OF SNOW ALONG AND BEHIND THE COLD FRONT. MVFR AND IFR CONDITIONS ARE LIKELY TO DEVELOP AT KRKS BETWEEN 22Z AND 01Z AND LAST A FEW HOURS. ALSO...VERY WINDY NORTHEAST/EAST WINDS WILL DEVELOP IN THE EVENING OVER SWEETWATER COUNTY. && .FIRE WEATHER... A COLD FRONT AND A COUPLE OF ASSOCIATED UPPER LEVEL DISTURBANCES WILL CROSS THE AREA TODAY AND BRING INCREASED CLOUD COVER ALONG WITH A GOOD CHANCE OF SNOW TODAY...ESPECIALLY EAST OF THE DIVIDE. GUSTY NORTH WINDS WILL ACCOMPANY THE SNOW...ESPECIALLY THIS AFTERNOON. BELOW NORMAL TEMPERATURES WILL CONTINUE INTO THE END OF THE WEEK ALONG WITH POOR SMOKE DISPERSAL AND LOW MIXING HEIGHTS. && .RIW WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY UNTIL MIDNIGHT MST TONIGHT WYZ008>010. && SHORT TERM...LIPSON LONG TERM...AEM AVIATION...WM FIRE WEATHER...LIPSON
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE RIVERTON WY 441 AM MST WED FEB 25 2015 WYZ001>020-022>030-261200- 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- 441 AM MST WED FEB 25 2015 ...WINTER WEATHER ADVISORY FOR THE BIGHORN MOUNTAIN AND NORTHERN JOHNSON COUNTY THROUGH WEDNESDAY EVENING... THIS HAZARDOUS WEATHER OUTLOOK IS FOR WESTERN AND CENTRAL WYOMING. .DAY ONE...TODAY AND TONIGHT SIGNIFICANT SNOW AND WIND ARE EXPECTED TO INCREASE OVER THE BIGHORN MOUNTAINS AND NORTHERN JOHNSON COUNTY THIS MORNING AND CONTINUE THROUGH THIS EVENING. PLEASE SEE THE WINTER WEATHER ADVISORY FOR MORE DETAILS. OTHERWISE...A CANADIAN COLD FRONT IS EXPECTED TO SPREAD SNOW AND AREAS OF BLOWING SNOW SOUTH MAINLY ALONG AND EAST OF THE DIVIDE TODAY...CAUSING SLICK ROADS WITH LIMITED VISIBILITY AT TIMES. .DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY SATURDAY...ANOTHER COLD FRONT WILL PLUNGE SOUTH AND LOOKS FAVORABLE TO BRING CHANCES OF SNOW TO MOST AREAS. THOUGH MANY AREAS WILL SEE SOME OPPORTUNITY FOR SNOWFALL...THE HIGHER TOTALS ARE EXPECTED ACROSS THE SOUTH. .SPOTTER INFORMATION STATEMENT... SPOTTERS ARE ENCOURAGE TO REPORT SNOWFALL AMOUNTS. TEAM RIVERTON
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE RIVERTON WY 348 AM MST WED FEB 25 2015 WYZ002>007-011-020-022-251800- ABSAROKA MOUNTAINS-CASPER MOUNTAIN-CODY FOOTHILLS- NATRONA COUNTY LOWER ELEVATIONS-NORTH BIG HORN BASIN- OWL CREEK AND BRIDGER MOUNTAINS-SOUTHEAST BIG HORN BASIN- SOUTHEAST JOHNSON COUNTY-SOUTHWEST BIG HORN BASIN- 348 AM MST WED FEB 25 2015 THE NEXT WEATHER SYSTEM WILL DRIVE A COLD FRONT SOUTH TODAY WITH LIGHT SNOW BREAKING OUT OVER THE AREA. THE SNOWFALL WILL BECOME LIGHT TO MODERATE LATER THIS MORNING AND WILL REMAIN FAIRLY STEADY TODAY. BY THURSDAY MORNING...1 TO 3 INCHES OF SNOWFALL WILL BE FAIRLY COMMON WITH 3 TO 6 INCHES IN THE MOUNTAINS ALONG WITH SOME LOCALLY HIGHER AMOUNTS AS THE HEAVIER NARROW SNOW BANDS SET UP. STAY TUNED FOR FURTHER STATEMENTS AND POSSIBLE ADVISORIES. WYZ015>019-251800- GREEN MOUNTAINS AND RATTLESNAKE RANGE-LANDER FOOTHILLS- UPPER WIND RIVER BASIN-WIND RIVER BASIN-WIND RIVER MOUNTAINS EAST- 348 AM MST WED FEB 25 2015 THE NEXT WEATHER SYSTEM WILL DRIVE A COLD FRONT SOUTH TODAY. WIDESPREAD LIGHT TO MODERATE SNOWFALL WILL DEVELOP THIS MORNING AND CONTINUE INTO TONIGHT. THE STEADIEST AND HEAVIEST SNOW IS EXPECTED THIS AFTERNOON AND EVENING. BY THURSDAY MORNING...1 TO 3 INCHES OF SNOWFALL WILL BE FAIRLY COMMON WITH 3 TO 6 INCHES IN THE MOUNTAINS ALONG WITH SOME LOCALLY HIGHER AMOUNTS AS THE HEAVIER NARROW SNOW BANDS SET UP. STAY TUNED FOR FURTHER STATEMENTS AND POSSIBLE ADVISORIES. WYZ028>030-251800- EAST SWEETWATER COUNTY-FLAMING GORGE-ROCK SPRINGS AND GREEN RIVER- 348 AM MST WED FEB 25 2015 A STRONG COLD FRONT WILL PUSH SOUTH AND WEST ACROSS SWEETWATER COUNTY THIS AFTERNOON AND EVENING. LIGHT TO MODERATE SNOWFALL IS EXPECTED TO DEVELOP ALONG AND BEHIND THIS COLD FRONT...AND THEN CONTINUE OFF AND ON TONIGHT. A TOTAL OF 1 TO 3 INCHES OF SNOW IS EXPECTED BY THURSDAY MORNING. A NORTHEAST TO EAST WIND...BETWEEN 15 AND 30 MPH...IN WAKE OF THE FRONT COULD CAUSE CONSIDERABLE BLOWING AND DRIFTING OF SNOW... AS WELL AS SEVERELY REDUCED VISIBILITY AT TIMES...ESPECIALLY OVER EASTERN SWEETWATER COUNTY THIS EVENING. STAY TUNED FOR FURTHER STATEMENTS AND POSSIBLE ADVISORIES. TEAM RIVERTON
The national radar mosaic for the moment the first event began.
1 winter weather. Local standard time, as filed.
Several wind gusts past 60 mph were recorded at the Johnson County Airport in Buffalo. The wind combined with a period of moderate to heavy snow that brought near whiteout conditions and led to several accidents and closures of interstates 25 and 90 for several hours.
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, February 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: 554046.