A cold front dropping south from Canada ushered into Wyoming some unusually cold air. This combined with deep moisture and favorable upper level dynamics to produce a heavy early season snow across portions of northern Wyoming.
Every event with a place to put it; 4 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 dropping south from Canada ushered into Wyoming some unusually cold air. This combined with deep moisture and favorable upper level dynamics to produce a heavy early season snow across portions of northern Wyoming. Johnson County was the hardest hit with up to 20 inches of snow in the higher elevations of the Bighorn Range. In the lower elevations, 7 to 10 inches of snow fell in Buffalo where the heavy, wet snow fell on trees that still had full leaf coverage. Broken tree limbs fell on power lines, which caused scattered power outages. Heavy snow also fell in the northwest portion of the Bighorn Range, with 16 inches recorded at the Shell Creek SNOTEL site. Lesser amounts of 6 to 8 inches were widespread in the eastern Absaroka Range. The early snow had impacts on ranchers who still had livestock in the higher elevations and on hunters.
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 Sep 10, 2:48 PM MST, 1 hour 12 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RIVERTON WY 348 PM MDT WED SEP 10 2014 .SHORT TERM...TODAY THROUGH THURSDAY NIGHT THE FIRST OF TWO WINTRY PUNCHES IS CURRENTLY UNDERWAY ACROSS NORTHEASTERN WYOMING. PORTIONS OF THE BIGHORN MOUNTAINS ARE EXPERIENCING SNOWFALL...WHICH IS EXPECTED TO PERSIST THIS AFTERNOON. THE LOWER ELEVATIONS OF JOHNSON COUNTY HAVE RECEIVED RAINFALL FOR THE BETTER PART OF THE DAY. THE SECOND...MORE POTENT PUNCH OF WINTRY WEATHER WILL OCCUR THIS EVENING. A STRONGER AND COLDER PUSH OF MOISTURE WILL MOVE ACROSS NORTHEASTERN WYOMING. THIS SYSTEM WILL BRING THE POTENTIAL FOR SIGNIFICANT SNOWFALL ACROSS NORTHEASTERN WYOMING...ESPECIALLY OVER THE BIGHORN MOUNTAINS AND NORTHERN JOHNSON COUNTY. THE NORTHERN THIRD OF THE ABSAROKA MOUNTAINS WILL ALSO SEE SIGNIFICANT ADVERSE IMPACTS FROM THIS SYSTEM. SNOWFALL OF 6 TO 10 INCHES WILL BE ANTICIPATED OVER THE NORTHERN PORTION OF THE ABSAROKA MOUNTAINS...WITH 7 TO 12 INCHES OVER THE NORTHERN BIGHORN MOUNTAINS...AND 3 TO 7 INCHES OVER NORTHERN JOHNSON COUNTY. TEMPERATURES OVER THE LOWER ELEVATIONS WILL KEEP SNOWFALL FROM ACCUMULATING VERY SIGNIFICANTLY ON ROADWAYS...BUT THE PERIODS OF MODERATE SNOWFALL WILL IMPACT TRAVEL AND VEGETATION ACROSS THE AREA. WINTER STORM WARNINGS HAVE BEEN ISSUED FOR NORTHERN JOHNSON COUNTY...THE BIGHORN MOUNTAINS...AND THE ABSAROKA MOUNTAINS. TO A LESSER EXTENT...MODERATE IMPACTS MAY BE SEEN OVER THE CODY FOOTHILLS AND SOUTHERN JOHNSON COUNTY. SNOWFALL IS ANTICIPATED OVER THESE AREAS...BUT ACCUMULATION IS NOT EXPECTED TO HAVE AS MUCH IMPACT AS THE PREVIOUSLY DISCUSSED AREAS. REGARDLESS...TRAVEL ROUTES WILL BE IMPACTED ALONG WITH VEGETATION...LEADING TO WINTER WEATHER ADVISORIES FOR THESE LOCATIONS. FOR SPECIFIC DETAILS ON TIMING...PLEASE REFER TO OUR WINTER WEATHER HIGHLIGHTS. .LONG TERM...FRIDAY THROUGH WEDNESDAY NIGHT A MUCH QUIETER PERIOD IS EXPECTED AS COMPARED TO MY ESTEEMED SHORT TERM COLLEAGUE. THE ONE CONCERN IS FOR THE POTENTIAL FOR A FREEZE WHERE SNOW DOES NOT OCCUR. WITH A RATHER COLD AIR MASS MOVING IN THE SKY EXPECTED TO CLEAR LATE AT NIGHT...MANY AREAS WILL FALL DOWN INTO THE 20S FOR LOW TEMPERATURES FRIDAY MORNING. AS A RESULT... WE WILL HOIST FREEZE WATCHES FOR THE LOWER ELEVATIONS EAST OF THE DIVIDE ANY TRACES OF THE STORM WILL HAVE EXITED TO THE SOUTH AND EAST BY FRIDAY MORNING. WE DID ADD SOME PATCHY FOG ACROSS AREAS WITH GREATER THAN 1 INCH OR SNOWFALL ACCUMULATION WITH SOME MELTING EXPECTED DUE TO WARM GROUND TEMPERATURES AND CLEARING LATE THURSDAY NIGHT. OTHERWISE...EXPECT TRANQUIL WEATHER THROUGH FRIDAY INTO SATURDAY. FLOW BECOMES ZONAL TO EVENTUALLY SOME RIDGING THAT WILL BRING MORE SUNSHINE ALONG WITH GRADUALLY WARMING TEMPERATURES WARMING BACK TO THE 60S FOR MANY LOWER ELEVATION LOCATIONS BY SATURDAY...WHICH WILL MAKE QUICK WORK OF ANY LEFTOVER SNOW ACCUMULATION. SUNDAY LOOKS MAINLY DRY FOR MOST AREAS. ONE FLY IN THE OINTMENT IS THE EUROPEAN WHICH BRINGS A WEAK SHORTWAVE THROUGH THE FLOW AND BRUSHES THE NORTHEASTERN AREAS WITH SOME QPF BUT UNTIL THERE IS MORE CONSISTENCY WE KEEP THINGS DRY. BY MONDAY TEMPERATURES LOOK TO BE NEAR TO ABOVE NORMAL FOR MOST LOCATIONS ONCE AGAIN. THE EUROPEAN TRIES TO CREEP SOME MONSOONAL MOISTURE BACK NORTHWARD INTO SWEETWATER COUNTY BUT THE OTHER MODELS ARE DRY SO AGAIN WE KEPT THINGS DRY. THE GENERAL PATTERN FOR EARLY NEXT WEEK LOOKS LIKE AN AMPLIFYING RIDGE OVER THE ROCKIES THAT WILL BRING ABOVE NORMAL TEMPERATURES. A WEAK SHORTWAVE MAY DROP TO MOVE INTO WESTERN AREAS FOR TUESDAY BUT AT THIS POINT IT APPEARS MOISTURE STARVED SO AGAIN WE LEFT THE FORECAST MAINLY DRY. && .AVIATION.../00Z ISSUANCE/ EAST OF THE DIVIDE...KCOD/KCPR/KLND/KRIW/KWRL ROUTES THE AVIATION COMMUNITY WILL SEE RAPIDLY DETERIORATING CONDITIONS TONIGHT ACROSS NORTHERN WYOMING. A STRONG WINTER-LIKE SYSTEM WILL IMPACT THE AREA...SPREADING MIXES OF RAIN AND SNOW NORTH AND EAST OF A LINE FROM KCOD-KRIW-KCPR. SOME TERMINALS WILL SEE PREVAILING SNOWFALL AFTER 09Z TONIGHT...AND POSSIBLY TO 18Z THURSDAY MORNING. WITH THE EXCEPTION OF KCOD...NONE OF THESE TERMINALS ARE TAF RECEIVING. KBYG WILL BE ONE OF THE MOST IMPACTED AIRPORTS THAT WILL RECEIVE SNOW TONIGHT INTO THURSDAY MORNING. PERIODS OF MVFR CONDITIONS ARE ANTICIPATED WITH THIS SYSTEM... WITH INSTANCES OF IFR CONDITIONS. THE WORST CONDITIONS WILL BE BETWEEN 03Z AND 18Z THURSDAY...AS PRECIPITATION AND COLD TEMPERATURES SPREAD SOUTH THROUGH THE AREA. SNOW...REDUCED VISIBILITIES...LOW CEILINGS...AND ICING CONDITIONS WILL ALL BE POSSIBLE DURING THIS TIME FRAME. MOUNTAIN AVIATION PASSES WILL ALSO BECOME HAZARDOUS DURING THIS SYSTEM...WITH INCREASED ICING AND TURBULENCE....AND MOUNTAIN OBSCURATION. WEST OF THE DIVIDE...KBPI/KJAC/KPNA/KRKS ROUTES THIS EVENING WILL SEE A FEW CLOUDS...ALONG WITH SOME GUSTY WINDS...FOR AREAS WEST OF THE DIVIDE. GUSTY WINDS WILL MOSTLY BE SEEN ACROSS SOUTHERN WYOMING...ESPECIALLY AT KRKS. AS A SYSTEM PUSHES THROUGH NORTHEASTERN WYOMING ON THURSDAY A RETURN OF GUSTY WIND WILL BEGIN AFTER 15Z THURSDAY. INCREASED CLOUD COVER WILL BE POSSIBLE OVER THE NORTHERN AND CENTRAL MOUNTAINS....WHICH MAY RESULT IN SOME MOUNTAIN OBSCURATION BETWEEN 00Z AND 06Z THIS EVENING. OTHERWISE...GENERALLY VFR CONDITIONS ANTICIPATED AT AIRPORTS. && .FIRE WEATHER... WINTRY SYSTEMS WILL IMPACT THE NORTHEASTERN HALF OF THE FORECAST AREA THROUGH THURSDAY EVENING. THIS WILL BRING COLDER TEMPERATURES...ALONG WITH SNOWFALL. SOME SNOWFALL MAY BE SIGNIFICANT...ESPECIALLY OVER THE ABSAROKA AND BIGHORN MOUNTAINS AND NORTHERN JOHNSON COUNTY AND A LESSER EXTEND OVER SOUTHERN JOHNSON AND THE CODY FOOTHILLS. THE SOUTHWESTERN HALF OF THE AREA WILL SEE MORE BENIGN CONDITIONS...WITH PARTLY CLOUD SKIES AND COOLER TEMPERATURES. SOME PERIODS OF GUSTY WIND WILL BE FOUND ACROSS THE SOUTH. OVERALL FIRE WEATHER CONCERNS ARE VERY LOW OVER THE NEXT COUPLE DAYS. && .RIW WATCHES/WARNINGS/ADVISORIES... WINTER STORM WARNING FROM 6 PM THIS EVENING TO 6 PM MDT THURSDAY WYZ002-008-009. FREEZE WATCH FROM LATE THURSDAY NIGHT THROUGH FRIDAY MORNING WYZ004>006-017-018-020. WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO 6 PM MDT THURSDAY WYZ003-011. WINTER STORM WARNING FROM MIDNIGHT TONIGHT TO 6 PM MDT THURSDAY WYZ010. && SHORT TERM...BRANHAM LONG TERM...HATTINGS AVIATION...ANGLIN FIRE WEATHER...BRANHAM
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE RIVERTON WY 330 PM MDT WED SEP 10 2014 WYZ001>020-022>030-111200- 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- 330 PM MDT WED SEP 10 2014 ...WINTER STORM WARNINGS AND ADVISORIES IN EFFECT FOR PORTIONS OF NORTHERN WYOMING TONIGHT THROUGH THURSDAY AFTERNOON... ...FREEZE WATCH IN EFFECT FOR THURSDAY NIGHT... THIS HAZARDOUS WEATHER OUTLOOK IS FOR WESTERN AND CENTRAL WYOMING. .DAY ONE...TONIGHT A DEEP STRONG UPPER LEVEL TROUGH AND A COUPLE OF ASSOCIATED STRONG COLD FRONTS WILL BRING THE POTENTIAL FOR SIGNIFICANT SNOW IN THE NORTHERN BIGHORN RANGE...NORTHERN ABSAROKA MOUNTAINS AND NORTHERN JOHNSON COUNTY...ESPECIALLY TONIGHT. THIS WILL INTRODUCE HAZARDOUS WINTER DRIVING CONDITIONS OVER MOUNTAIN PASSES. ADDITIONALLY...A FEW INCHES OF SNOW MAY ACCUMULATE ELSEWHERE IN THE LOWER ELEVATIONS ACROSS NORTHERN WYOMING LATE TONIGHT. .DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY THURSDAY...A STRONG EARLY WINTER WEATHER SYSTEM WILL CONTINUE THE POTENTIAL FOR SIGNIFICANT SNOW IN THE NORTHERN BIGHORN RANGE... NORTHERN ABSAROKA MOUNTAINS AND NORTHERN JOHNSON COUNTY. THIS WILL CONTINUE HAZARDOUS WINTER DRIVING CONDITIONS OVER MOUNTAIN PASSES. THURSDAY NIGHT AND FRIDAY...A WIDESPREAD FREEZE OR FROST POSSIBLE ACROSS THE LOWER ELEVATIONS OF CENTRAL WYOMING FRIDAY MORNING. MORNING FOG IS ALSO POSSIBLE IN THE SAME AREA. .SPOTTER INFORMATION STATEMENT... SPOTTERS ARE ENCOURAGED TO REPORT ANY SNOWFALL AMOUNTS. THANK YOU. TEAM RIVERTON
The national radar mosaic for the moment the first event began.
4 winter storm. Local standard time, as filed.
Heavy snow fell across the eastern Bighorn Range. The maximum was 20 inches at the Little Goose SNOTEL.
The SNOTEL at Shell Creek reported 16 inches of snow.
Widespread 6-8 inch snowfall totals were observed in the Absaroka Range.
There were widespread reports of 7 to 10 inches of snow throughout Buffalo. The snow fell on trees with full foliage, resulting in many downed limbs and scattered power outages throughout Buffalo.
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, September 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: 534500, 534498, 539650, 534501.