An intense upper level low west of Wyoming provided a favorable pressure gradient for southwest wind to blow in a wind-prone corridor in central Wyoming. Sustained speeds of 40 mph with gusts around 60 mph were common for several midday hours.
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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 intense upper level low west of Wyoming provided a favorable pressure gradient for southwest wind to blow in a wind-prone corridor in central Wyoming. Sustained speeds of 40 mph with gusts around 60 mph were common for several midday hours. An automated sensor near Hiland recorded a peak gust to 61 mph shortly before 1200MST, while a station north of Casper topped out at 59 mph less than one hour later. Along US Highway 287 in southern Fremont County, sustained speeds of 40 to 45 mph were observed over Beaver Rim.
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 13, 1:41 AM MST, 8 hours 19 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RIVERTON WY 241 AM MDT TUE APR 13 2010 .SHORT TERM...TODAY THROUGH THURSDAY NIGHT A NEGATIVELY TILTED BROAD UPPER LEVEL TROUGH CONTINUES TO INCH NORTHEASTWARD TOWARD WESTERN WYOMING THIS MORNING. NUMERICAL MODELS IN FAIR AGREEMENT WITH ONE ANOTHER...CLOSING OFF AND CONTINUING TO EJECT THIS UPPER LOW NORTHEASTWARD THROUGH FAR NORTHWEST WYOMING THROUGH THE DAY. HIGH WIND OVER PORTIONS OF CENTRAL AND SOUTHEAST WYOMING EXPECTED TO BE THE INITIAL IMPACT FROM THIS SYSTEM THIS MORNING...CONTINUING THROUGH THE EARLY EVENING. UPGRADED HIGH WIND WATCH TO A HIGH WIND WARNING FOR WYZ019 AND WYZ020. DELAYED TIMING OF FOR WYZ019 BY THREE HOURS WITH THE LATEST MODEL GUIDANCE ABOUT THREE HOURS SLOWER TRANSITIONING THE H7 AND NEAR SFC WIND MAXIMA OVER THE LOWER ELEVATIONS OF NATRONA COUNTY. 00Z GFS RUN TO RUN CONSISTENTLY IMPROVING WITH THE PAST 4 RUNS OR SO...COMING IN LINE WITH THE ECMWF SOLUTION...PROGGING A SFC LOW TO DEEPEN RAPIDLY OVER NORTHEAST WYOMING EARLY THIS MORNING. THIS SURFACE AND THE UPPER LEVEL TRACK TAKING A PATH NOT FAVORABLE FOR WIDESPREAD PRECIPITATION FOR AREAS EAST OF THE DIVIDE. THE CLOSED H7 CIRCULATION PROGGED BY THE GFS...ECMWF...AND GEM TO DEVELOP OVER THE SOUTHERN END OF THE NORTHERN ROCKIES THIS MORNING...THEN TRACKING IT EASTWARD TO NEAR A BILLINGS TO SHERIDAN LINE AROUND MIDDAY. THE VERY STRONG TO HIGH SOUTHWEST WIND WILL SHUT OFF MOST PRECIPITATION EAST OF THE DIVIDE...OUTSIDE OF THE BIGHORN MOUNTAINS LATE THIS MORNING THROUGH THIS AFTERNOON. SIGNIFICANTLY LOWERED PRECIP/SHOWER CHANCES IN THE BASIN EAST OF THE DIVIDE AS A RESULT OF THIS STRONG DOWNSLOPING. CLOSED UPPER LOW CONTINUES TO MOVE RAPIDLY NORTH- NORTHEAST INTO NORTHEAST MONTANA THIS EVENING...WITH MAINLY OROGRAPHIC PRECIPITATION CONTINUING OVER THE NORTHERN MOUNTAINS TONIGHT. KEPT A MENTION OF SHOWERS IN THE FORECAST WITH A SLIGHTLY UNSTABLE AIRMASS IN PLACE...COULD NOT RULE OUT A STRAY PASSING SHOWER TO TWO. DRY WESTERLY FLOW ALOFT AHEAD OF A STRENGTHENING SHORT- WAVE RIDGE WILL TRANSITION OVER THE REGION WEDNESDAY...AND CONTINUE A DRYING AND WARMING TREND THROUGH AT LEAST THURSDAY NIGHT. .LONG TERM...FRIDAY THROUGH TUESDAY A MAINLY DRY DAY IS EXPECTED ON FRIDAY...AHEAD OF A SHORTWAVE TROUGH PUSHING ACROSS THE GREAT BASIN. MEDIUM RANGE MODELS ARE STILL HAVING A DIFFICULT TIME HANDLING THIS SYSTEM...AS THE ECMWF AND UKMET STILL WANT TO CUT OFF THIS SYSTEM OVER THE DESERT SOUTHWEST FRIDAY NIGHT...AND THE SLOWLY MOVE IT EAST ACROSS NEW MEXICO AND ARIZONA THIS WEEKEND. ON THE OTHER HAND...THE GFS AND GEM HAVE BEEN RELATIVELY CONSISTENT IN SWINGING THIS SHORTWAVE TROUGH THROUGH THE AREA FRIDAY NIGHT/SATURDAY. THEN...AN UPPER LOW PROJECTED BY MEDIUM RANGE MODELS TO BE OFF THE NORTHERN CALIFORNIA COAST SATURDAY IS PROJECTED TO OPEN UP AND PUSH EAST NORTHEAST INTO THE INTERMOUNTAIN WEST BY SUNDAY...THEN ACROSS THE AREA SUNDAY NIGHT. DETAILS WITH THIS SYSTEM ALSO REMAINS SKETCHY AT BEST. THEN AFTER THIS SYSTEM ON SUNDAY...A MORE ROBUST TROUGH IS EXPECTED TO PUSH INTO THE WEST COAST LATE MONDAY/TUESDAY. DUE TO LARGE UNCERTAINTY IN MODEL SOLUTIONS AND DETAILS...HAVE CONTINUED TO BROAD BRUSH POPS...MAINLY SLIGHT VALLEY/LOW CHANCE MTS...FRIDAY NIGHT THROUGH SUNDAY NIGHT. NOT EXPECTING A PROLONGED PERIOD OF PRECIPITATION...BUT COULD SEE A COUPLE ROUNDS OF PRECIPITATION...THAT CAN BE NARROWED DOWN AS THE TIME DRAWS CLOSER. TEMPERATURES ARE EXPECTED TO BE GENERALLY ABOVE AVERAGE THROUGH THE EXTENDED. && .AVIATION... A STORM SYSTEM WILL MOVE THROUGH THE REGION TODAY. SCATTERED SHOWERS WILL OCCUR OVER THE AREA WITH SNOW IN THE MOUNTAINS. OVER NORTHERN AND WESTERN WY AREAS OF MVFR TO IFR CONDITIONS WILL OCCUR TODAY DUE TO LOW CLOUDS AND PRECIPITATION. VFR CONDITIONS WILL PREVAIL IN SOUTHERN AND MOST OF CENTRAL WY. EXPECT WINDY WEATHER OVER ALL BUT NORTHERN WY TODAY. WIND SPEEDS ACROSS CENTRAL AND SOUTHERN WY WILL RANGE FROM 25 TO 35 KNOTS WITH LOCALLY 40 KNOTS NEAR KCPR AIRPORT. WIND GUSTS OF 45 TO 50 KNOTS ARE EXPECTED AROUND THE KCPR AIRPORT. SCATTERED SNOW SHOWERS WILL PERSIST IN NW WY AND OVER THE BIGHORN MTS AFTER 00Z WITH MVFR TO IFR CONDITIONS. OTHERWISE VFR CONDITIONS WILL OCCUR AFTER 00Z. WIND SPEEDS WILL SUBSIDE IN ALL AREAS AFTER 00Z. && .FIRE WEATHER... WIDESPREAD WINDY CONDITIONS ARE EXPECTED IN THE CENTRAL BASINS OF WYOMING TODAY. VERY STRONG TO HIGH WIND IS EXPECTED FROM NORTHEAST FREMONT COUNTY THROUGH MOST OF NATRONA COUNTY THROUGH EARLY EVENING. COOLER CONDITIONS WITH WIDESPREAD ACCUMULATING SNOW WILL FALL IN THE NORTHWEST MOUNTAINS THROUGH THIS EVENING BEFORE TAPERING OFF LATE TONIGHT. A WARMING TREND ALONG WITH MODERATE WEST WIND AND FAIR TO GOOD SMOKE DISPERSAL IS ANTICIPATED FOR WEDNESDAY. && .RIW WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY UNTIL 6 PM MDT TUESDAY WYZ001-002-012. HIGH WIND WARNING FROM 6 AM TO 6 PM MDT TUESDAY WYZ019. HIGH WIND WARNING FROM 9 AM TO 6 PM MDT TUESDAY WYZ020. && SHORT TERM...CHURCH LONG TERM...WM AVIATION...AR FIRE WEATHER...CHURCH
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE RIVERTON WY 600 AM MDT TUE APR 13 2010 WYZ001>020-022>030-141200- 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- 600 AM MDT TUE APR 13 2010 ...HIGH WIND WARNING FOR SOUTHEAST FREMONT COUNTY AND MUCH OF NATRONA COUNTY TODAY... ...WINTER WEATHER ADVISORY FOR THE TETONS...GROS VENTRES... YELLOWSTONE NATIONAL PARK AND THE ABSAROKA MOUNTAINS THROUGH 6 PM TODAY... THIS HAZARDOUS WEATHER OUTLOOK IS FOR WESTERN AND CENTRAL WYOMING. .DAY ONE...TODAY AND TONIGHT A PACIFIC STORM SYSTEM WILL BRING VERY STRONG TO POTENTIALLY DAMAGING WIND FROM JEFFREY CITY TO CASPER TODAY. SOUTHWEST WINDS OF 35 TO 45 MPH WITH GUSTS OVER 60 MPH ARE ANTICIPATED. LOCALIZED WIND GUSTS UP TO 70 MPH ARE POSSIBLE. THE SAME STORM SYSTEM WILL BRING SNOWFALL TO MANY AREAS OF NORTHWEST WYOMING TODAY. THE HARDEST HIT AREAS WILL BE THE NORTHWEST MOUNTAINS WHERE 6 TO 12 INCHES WITH LOCALLY HIGHER AMOUNTS ARE EXPECTED BY THIS EVENING. FOUR TO EIGHT INCHES OF ACCUMULATION ARE POSSIBLE IN THE THE BIGHORN MOUNTAINS ABOVE ABOUT 7500 FEET TODAY. TRAVEL OVER THE PASSES IN THESE AREAS WILL LIKELY BE IMPACTED WITH SLICK...SNOWPACKED ROAD SURFACES. .DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY THE POTENTIAL FOR WIDESPREAD HAZARDOUS WEATHER IS LOW. .SPOTTER INFORMATION STATEMENT... SPOTTERS ARE ASKED TO REPORT WIND SPEEDS OVER 40 MPH AND SNOWFALL OVER 2 INCHES. THANK YOU. TEAM RIVERTON
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE RIVERTON WY 642 AM MDT TUE APR 13 2010 WYZ013-023-131600- JACKSON HOLE-STAR VALLEY- 642 AM MDT TUE APR 13 2010 PERIODS OF SNOW...MODERATE AT TIMES...IS EXPECTED TO CONTINUE THIS MORNING. ONE TO THREE INCHES WILL BE POSSIBLE...WITH MOST OF THE ACCUMULATION OCCURRING ON ELEVATED AND GRASSY AREAS. MOST ROADS WILL LIKELY REMAIN MAINLY WET...BUT SOME ROADS WILL BECOME SLICK OR SLUSHY IN HEAVIER SNOW ACROSS JACKSON HOLE AND STAR VALLEY. TETON AND TOGWOTEE PASSES WILL BE SLICK AND HAZARDOUS TODAY. VISIBILITY IN THE HEAVIER SNOW...WILL BE REDUCED TO AROUND A HALF A MILE. 21
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE RIVERTON WY 727 AM MDT TUE APR 13 2010 WYZ023-131700- STAR VALLEY- 727 AM MDT TUE APR 13 2010 THE SNOW WILL GRADUALLY WIND DOWN AND TAPER OFF BY LATE MORNING OVER THE STAR VALLEY. EXPECT ANOTHER INCH OR LESS OF ACCUMULATION...MAINLY OVER THE NORTHERN HALF OF THE VALLEY. SECONDARY ROADS WILL LIKELY BE SLUSHY TO SNOW COVERED...WITH SLUSHY TO WEST CONDITIONS ON PRIMARY ROAD SURFACES. HOWEVER...SNAKE CANYON WILL BE SNOW COVERED TO SLUSHY THIS MORNING. TWB
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE RIVERTON WY 916 AM MDT TUE APR 13 2010 WYZ015-132200- WIND RIVER MOUNTAINS EAST- 916 AM MDT TUE APR 13 2010 STRONG WIND WILL CONTINUE OVER SOUTH PASS AS WELL AS THE REMAINDER OF THE EAST SLOPES OF THE WIND RIVER MOUNTAINS TODAY. WEST WINDS OF 40 TO 50 MPH WITH GUSTS TO 70 MPH CAN BE EXPECTED. BLOWING SNOW WILL BE ENCOUNTERED AS WELL...CREATING SOME WHITEOUT CONDITIONS. TRAVELLERS SHOULD BE AWARE OF THESE STRONG WINDS BEFORE TRAVELLING OVER SOUTH PASS. TWB
The national radar mosaic for the moment the first event began.
2 high wind. Local standard time, as filed.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Wyoming in 2010Every state in 2010This day in weather historyWarnings in Wyoming, April 2010
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: 215845, 215844.