An upper level disturbance brought cold temperatures and heavy snow to many areas east of the Continental Divide. The heaviest snow fell across areas of Fremont and Natrona counties favored by northeast, upslope flow.
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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.
An upper level disturbance brought cold temperatures and heavy snow to many areas east of the Continental Divide. The heaviest snow fell across areas of Fremont and Natrona counties favored by northeast, upslope flow. Snowfall of one to two feet fell in the southern Wind River Range and on Casper Mountain. In addition, convective banding brought heavy snow to portions of the eastern Big Horn Basin. Snowfall of 8 to 12 inches fell in central Big Horn County around Greybull, Basin, and Otto.
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 Apr 12, 1:06 PM MST, 3 hours 54 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RIVERTON WY 206 PM MDT SAT APR 12 2014 .SHORT TERM...TONIGHT THROUGH SUNDAY AS AN UPPER LEVEL LOW PRESSURE TROUGH DIGS SOUTHEAST ACROSS IDAHO... A COLD FRONT WILL MOVE SOUTH FROM MONTANA SATURDAY EVENING. THE UPPER TROUGH WILL PRODUCE FAIRLY STRONG UPPER DIVERGENCE OVER MUCH OF WESTERN AND CENTRAL WYOMING...ESPECIALLY OVER THE COLD FRONT. THE MID LEVELS WILL DESTABILIZE WITH INCREASING DEFORMATION AND FRONTOGENETIC FORCES INCREASING THE BAROCLINICITY ALONG THE COLD FRONT. AHEAD OF THE COLD FRONT...DEEP CONVECTION WILL BE POSSIBLE WITH A THREAT OF AT LEAST ISOLATED THUNDERSTORMS...EMBEDDED IN A LARGER FIELD OF SHOWERS. SMALL HAIL AND GUSTY WINDS MAY ACCOMPANY THE THUNDERSTORMS WHICH WILL BE ACROSS CENTRAL AND SOUTHERN AREAS AS WELL AS THE MOUNTAINS WEST OF THE CONTINENTAL DIVIDE. BEHIND THE COLD FRONT THE PRECIPITATION MAY START OUT AS RAIN EARLY IN THE EVENING...BUT TEMPERATURES ALOFT COOL QUICKLY AND EXPECT A QUICK CHANGE OVER TO SNOW. THE SNOW SHOULD BE WET AROUND A 10 TO 1 RATIO AND WITH SOME CONVECTIVE NATURE WITH AT LEAST MID LEVEL INSTABILITY SUPPORTING LOW LEVEL CONVERGENCE...SNOWFALL RATES OF 1 TO 1.5 INCHES AN HOUR ARE POSSIBLE. THE STRONGEST PERIOD OF SNOWFALL SHOULD BE FROM LATE EVENING TO EARLY MORNING SUNDAY...OR ABOUT 9 TO 10 HOURS AND THIS SHOULD HELP DETERMINE ACCUMULATION POTENTIAL. THERE WILL LIKELY BE AN OROGRAPHIC COMPONENT TO THE SNOWFALL DISTRIBUTION WITH HIGHER AMOUNTS IN THE NORTHERN BIGHORN MOUNTAINS...CASPER MOUNTAIN...THE OWL CREEK AND BRIDGER RANGES AND THE EAST SLOPES OF THE WIND RIVER RANGE EXTENDING EAST ALONG THE NORTH SLOPES OF THE GRANITE AND GREEN MOUNTAINS. HAVE CONTINUED WIN STORM WARNINGS AND ADVISORIES AS ISSUED FOR MUCH OF THE AREA EAST OF THE CONTINENTAL DIVIDE FROM 03Z SUNDAY THROUGH 21Z SUNDAY. EXPECT ACCUMULATIONS TO DECREASE FROM NOON TO 3 PM AND DRYING SPREADING SOUTH THROUGH THE AFTERNOON AND SUNDAY EVENING. .LONG TERM...SUNDAY NIGHT THROUGH SATURDAY SLOW CLEARING FROM NORTH TO SOUTH SUNDAY NIGHT AS OUR WINTER STORM EXITS INTO COLORADO. WAA ASSOCIATE WITH A RIDGE BUILDING TO OUR WEST WILL ENCOURAGE FOG FORMATION IN BASINS AND VALLEYS AS THE FRESH SNOW COVER LEAVES BEHIND A MOIST BOUNDARY LAYER AND LIGHT SURFACE WINDS. MODELS HAVE BEEN BACKING OFF ON A STRONGER RIDGE HOLDING ITS PLACE OVER WYOMING ON TUESDAY...NOW THERE ARE SOME HINTS AT ANOTHER STORM SYSTEM MOVING INTO THE NORTHWEST BY TUESDAY AFTERNOON AND THEN GRAZES THE NORTHERN THIRD OF THE REGION WEDNESDAY WITH A SECONDARY MOISTURE FEED MOVING INTO SOUTHERN WYOMING WITH SOME INSTABILITY KICKING OFF SOME SHOWERS IN THE AFTERNOON ACROSS SWEETWATER COUNTY. THE STRENGTH AND THE TRACK OF MAIN MOISTURE REMAINS UNCLEAR AS THE GFS AND GEM MODELS HAVE BEEN MORE BULLISH THAN THE ECMWF...BUT THE LATEST RUN IS BRINGING IT CLOSER INTO LINE WITH THE GFS. THE SYSTEM MOVES OUT EARLY ON THURSDAY TAKING THE PRECIP WITH IT FOR THE MOST PART. LINGERING MOUNTAIN SNOW SHOWERS ARE POSSIBLE AND ISOLATED SHOWERS EAST OF THE DIVIDE BUT THURSDAY LOOKS DRY FOR MOST OF THE REGION. THE MODELS DIVERGE QUITE A BIT AFTER THURSDAY WITH THE GFS ADVERTISING STRONG CYCLOGENESIS IN THE PLAINS WITH SOME COOL AIR AND SHOWERS HANGING AROUND WYOMING WHILE THE EUROPEAN KEEPS THE FLOW ZONAL WITH MILD AIR STARTING TO BUILD IN FROM THE SOUTH. AS FOR NEXT FRIDAY...ALL GLOBAL MODELS BRING ANOTHER STORM SYSTEM INTO THE REGION...WITH VARIED TIMING AND STRENGTH. TEMPERATURES WILL BE KEY AS SOME MODELS START THE PRECIP EARLY...AND WITH A MORE ZONAL FLOW THAT COULD MEAN SOME RAIN FOR THE JACKSON AREA AND BAD NEWS FOR THE LAND SLIDE...OTHERS DIG THE SYSTEM A BIT MORE AND BRING IN SOUTHWEST FLOW AND COOLER TEMPERATURES...WHICH WOULD LEAN TOWARD SNOW. WILL KEEP CONTINUITY AS THE PREVIOUS SHIFT HAS IT COVERED PRETTY WELL...BRING IN LOW PRECIP CHANCE TO THE WEST THURS NIGHT. THEN A BETTER CHANCE OF PRECIP FRIDAY AND FRI NIGHT OVER THE WEST. WILL HAVE A LOW CHANCE OF PRECIP EAST OF THE DIVIDE FOR FRIDAY AFTERNOON AND FRI NIGHT. NEXT SATURDAY LOOKS DRY FOR MOST AREAS...ISOLATED SHOWERS IN THE WESTERN MOUNTAINS MAINLY FOR THE AFTERNOON AND EVENING HOURS. HIGH TEMPS ON TUESDAY LOOK TO BE MILDER...THEN COOLER ON WED DUE TO THE WEATHER SYSTEM. THURS LOOKS TO WARM UP A LITTLE. FRI WILL BE A TAD MILDER EAST OF THE DIVIDE AHEAD OF THE WEATHER SYSTEM WHILE THE WEST IS NEAR OR SLIGHTLY COOLER TO THE THURS HIGHS. && .AVIATION.../00Z ISSUANCE/ WEST OF THE DIVIDE...KJAC/KPNA/KBPI/KRKS ROUTES VFR CONDITIONS WILL PREVAIL THROUGH 03Z. INCREASING MOISTURE AND INSTABILITY WILL INITIALLY BRING SCT SHRA AND ISOLD TSRA VCNTY AND SOUTH OF INTERSTATE 80 AND INTO THE NW CORNER OF WYOMING THRU 06Z. A COLD FRONT WILL SPREAD NMRS SHSN AND WIDESPREAD MTN OBSCURATIONS SOUTH FROM MONTANA TO A VCNTY KJAC- KDUB LINE BTWN 03Z-06Z. INCREASING NE DOWNSLOPE FLOW WILL RESULT IN SOME IMPROVEMENT ACROSS THE NW AFTER 12Z. RAIN AND SNOW WITH WIDESPREAD IFR/LIFR CONDITIONS...WILL DEVELOP PRIMARILY FROM KRKS TO THE SOUTH PASS AREA 03Z-09Z AS THE COLD FRONT PLUNGES SOUTH ACROSS SW WYOMING. EAST OF THE DIVIDE...KCPR/KCOD/KLND/KRIW/KWRL ROUTES VFR CONDITIONS WILL PREVAIL ACROSS THE AREA WILL GIVE WAY TO WIDESPREAD RAIN AND SNOW SPREADING RAPIDLY SOUTH ACROSS THE NORTH AFTER 00Z REACHING THE SOUTH BY 06Z. THE RAIN OR RAIN/SNOW MIX WITH MVFR/IFR CONDITIONS WILL LAST A COUPLE OF HOURS WITH THE INITIAL FRONTAL BAND WITH SNOW LEVELS RAPIDLY LOWERING BEHIND THE FRONT. EXPECT WIDESPREAD IFR/LIFR CONDITIONS VCNTY AND NORTH OF A KCOD- KBYG LINE BY 00Z SPREADING TO A VCNTY KLND-KCPR LINE BETWEEN 03Z-06Z. && .FIRE WEATHER... A STRONG WET COLD FRONT WILL BRING WIDESPREAD SNOW TO MUCH OF THE AREA TONIGHT AND INTO SUNDAY AFTERNOON. SIGNIFICANT SNOW ACCUMULATIONS ARE POSSIBLE...ESPECIALLY ALONG AND NEAR NORTH AND EAST FACING SLOPES. THE SNOW WILL TAPER OFF SUNDAY AFTERNOON ENDING IN THE EVENING. TEMPERATURES WILL BE MUCH COLDER THROUGH MONDAY. MIXING HEIGHTS WILL BE VERY LOW WITH GENERALLY POOR SMOKE DISPERSAL. && .RIW WATCHES/WARNINGS/ADVISORIES... WINTER STORM WARNING FROM 9 PM THIS EVENING TO 3 PM MDT SUNDAY WYZ015-018>020-022. WINTER WEATHER ADVISORY FROM 9 PM THIS EVENING TO 3 PM MDT SUNDAY WYZ004>007-010-011-016-017. WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO NOON MDT SUNDAY WYZ002. WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 3 PM MDT SUNDAY WYZ008-009. WINTER STORM WARNING FROM 6 PM THIS EVENING TO NOON MDT SUNDAY WYZ003. && SHORT TERM...C.BAKER LONG TERM...ALLEN AVIATION...C.BAKER FIRE WEATHER...C.BAKER
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE RIVERTON WY 324 PM MDT SAT APR 12 2014 WYZ001>020-022>030-131100- 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- 324 PM MDT SAT APR 12 2014 ...WINTER STORM WARNINGS AND WINTER WEATHER ADVISORIES FOR MUCH OF CENTRAL WYOMING TONIGHT AND SUNDAY... THIS HAZARDOUS WEATHER OUTLOOK IS FOR WESTERN AND CENTRAL WYOMING. .DAY ONE...TODAY AND TONIGHT THIS AFTERNOON ISOLATED THUNDERSTORMS WITH STRONG WIND GUSTS AND SMALL HAIL WILL BE POSSIBLE. TONIGHT...RAIN SHOWERS WILL CHANGE TO SNOW AND MAY BECOME HEAVY AT TIMES ACROSS THE NORTH AND CENTRAL AREAS. AREAS OF STRONG NORTH WINDS WILL CAUSE SOME BLOWING SNOW. PLEASE SEE WINTER STORM WARNINGS AND WINTER WEATHER ADVISORIES FOR DETAILS. .DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY SUNDAY...PERIODS OF SNOW WILL CONTINUE...ESPECIALLY EAST OF THE DIVIDE. SNOW ENDS FROM NORTH TO SOUTH DURING THE AFTERNOON HOURS. HAZARDOUS TRAVEL IS LIKELY SUNDAY MORNING. TUESDAY NIGHT THROUGH WEDNESDAY NIGHT...A WEATHER SYSTEM IS TO BRING A CHANCE OF RAIN AND SNOW TO NORTHWEST WYOMING TUESDAY NIGHT. THEN A CHANCE OF RAIN AND SNOW SPREADS OVER MOST OF THE REGION WEDNESDAY INTO WEDNESDAY NIGHT. TIMING COULD CHANGE...SO CHECK BACK FOR UPDATES IN THE COMING DAYS. .SPOTTER INFORMATION STATEMENT... SPOTTERS ARE URGED TO REPORT SNOWFALL MEASUREMENTS TONIGHT AND SUNDAY. TEAM RIVERTON
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE RIVERTON WY 236 PM MDT SAT APR 12 2014 WYZ028>030-122115- EAST SWEETWATER COUNTY WY-FLAMING GORGE WY-ROCK SPRINGS AND GREEN RIVER WY- 236 PM MDT SAT APR 12 2014 ...SIGNIFICANT WEATHER ADVISORY FOR CENTRAL SWEETWATER COUNTY UNTIL 315 PM MDT... AT 235 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR WAS TRACKING A STRONG THUNDERSTORM NEAR GREEN RIVER...MOVING NORTHEAST AT 25 MPH. HAIL UP TO ONE-HALF INCH IN DIAMETER AND WIND GUSTS UP TO 40 MPH ARE EXPECTED WITH THIS STORM...ALONG WITH FREQUENT DANGEROUS LIGHTNING. THIS STORM WILL BE NEAR... I80 EXIT 91 AROUND 245 PM MDT. JCT I80 AND HWY 191 AROUND 305 PM MDT. I80 EXIT 102 AND PILOT BUTTE AROUND 310 PM MDT. ROCK SPRINGS AND SWEETWATER COUNTY FAIRGROUNDS AROUND 315 PM MDT. THIS INCLUDES INTERSTATE 80 IN WYOMING BETWEEN MILE MARKERS 85 AND 108. IF THREATENING WEATHER APPROACHES YOUR AREA...TAKE SHELTER IN A STURDY BUILDING. REPORT HAZARDOUS WEATHER TO THE NATIONAL WEATHER SERVICE OFFICE IN RIVERTON AT 1-800-211-1448. LAT...LON 4172 10928 4149 10910 4135 10953 4151 10965 TIME...MOT...LOC 2036Z 240DEG 20KT 4147 10949 C. BAKER
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE RIVERTON WY 245 PM MDT SAT APR 12 2014 WYZ019-020-122130- GREEN MOUNTAINS AND RATTLESNAKE RANGE WY-NATRONA COUNTY LOWER ELEVATIONS WY- 245 PM MDT SAT APR 12 2014 ...SIGNIFICANT WEATHER ADVISORY FOR SOUTHWESTERN NATRONA COUNTY UNTIL 330 PM MDT... AT 242 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR WAS TRACKING A STRONG THUNDERSTORM NEAR SPLIT ROCK...OR 17 MILES EAST OF JEFFREY CITY...MOVING EAST AT 30 MPH. HAIL UP TO ONE-HALF INCH IN DIAMETER AND WIND GUSTS UP TO 40 MPH ARE EXPECTED WITH THIS STORM...ALONG WITH FREQUENT DANGEROUS LIGHTNING. THIS STORM WILL BE NEAR... U.S. HWY 220 MILE MARKER 70 AROUND 330 PM MDT. IF THREATENING WEATHER APPROACHES YOUR AREA...TAKE SHELTER IN A STURDY BUILDING. REPORT HAZARDOUS WEATHER TO THE NATIONAL WEATHER SERVICE OFFICE IN RIVERTON AT 1-800-211-1448. LAT...LON 4284 10698 4248 10688 4245 10752 4262 10754 TIME...MOT...LOC 2045Z 253DEG 26KT 4253 10748 C. BAKER
The national radar mosaic for the moment the first event began.
7 winter storm. Local standard time, as filed.
A trained spotter reported 7 inches of snow in Meeteetsee.
Snowfall of 12 to 15 inches was measured on Casper Mountain.
Mesoscale convective banding produced locally heavy snowfall in the northern Big Horn Basin. At Greybull 11 inches of snow fell with 9 inches reported at Otto.
A NWS employee measured 6 inches of snow in Lander.
Six inches of snow fell on the south side of Casper.
A spotter 9.5 miles SW of Lander measured 16 inches of snow.
Snowfall of 6 to 10 inches fell along Beaver Rim.
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, April 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: 506293, 506300, 506297, 506294, 506296, 506299, 509293.