A storm system moving into Wyoming from the Great Basin brought high wind to the Green Mountains and Rattlesnake Hills as well as the lower elevations of Natrona County. Wind gusts of 83 and 84 mph were recorded at two RAWS sites.
Every event with a place to put it; 2 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 storm system moving into Wyoming from the Great Basin brought high wind to the Green Mountains and Rattlesnake Hills as well as the lower elevations of Natrona County. Wind gusts of 83 and 84 mph were recorded at two RAWS sites. Wind was sustained at 40 mph for three hours along Interstate 25 north of Casper.
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 Oct 6, 2:35 PM MST, 6 hours 55 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RIVERTON WY 335 PM MDT THU OCT 6 2011 .SHORT TERM...TONIGHT THROUGH SATURDAY STORM SYSTEM SPINNING UP NEAR PRICE UTAH THIS AFTERNOON WITH LIGHT TO MODERATE SNOW FALLING SINCE THIS MORNING OVER MUCH OF WESTERN WYOMING. 3 INCHES OF SNOW HAS FALLEN SO FAR AROUND STAR VALLEY RANCH. BAROCLINIC LEAF MOVING THROUGH SOUTH CENTRAL WYOMING THIS AFTERNOON WITH DECENT CONVECTION DEVELOPING THERE. A FEW LIGHTNING STRIKES HAVE BEEN NOTED. ALSO HAVE TROWAL OVER SOUTHWEST WYOMING STREAMING INTO EASTERN AND CENTRAL IDAHO...WITH SOME LIGHT TO OCCASIONALLY MODERATE SNOWFALL THERE. LOW LIFTS NORTHEAST ACROSS WYOMING THIS EVENING AND OVERNIGHT WITH THE TROWAL/WARM CONVEYOR BELT SETTING UP OVER NORTHWEST AND NORTHERN WYOMING TONIGHT THROUGH FRIDAY MORNING. THE HEAVIEST PRECIPITATION LOOKS TO BE OVER NORTH CENTRAL WYOMING. SNOW LEVELS ACROSS THE WEST AND SOUTH WILL EASILY BE AT THE VALLEY FLOORS...WHILE EAST OF THE DIVIDE...SNOW LEVELS WILL BE DOWN TO BETWEEN 6500 AND 7000 FEET. WILL ALLOW CURRENT ADVISORIES TO RUN THEIR COURSE...AND WILL ADD THE STAR VALLEY AND JACKSON HOLE TO THE MIX (ALL THROUGH 9 AM). WILL GO AHEAD WITH A WARNING FOR THE BIGHORN MOUNTAINS FROM 9 PM THIS EVENING THROUGH NOON FRIDAY WITH 8 TO 14 INCHES EXPECTED THERE. THE PRECIPITATION WILL WIND DOWN BY LATE MORNING AS THE DYNAMICS LIFT NORTH. HIGH WINDS ARE EXPECTED OVERNIGHT BETWEEN EASTERN SWEETWATER...SOUTHEAST FREMONT AND NATRONA COUNTIES AS JET ROUNDS THE LOW AND LIFTS NORTHEAST OVER COLORADO AND SOUTHEAST WYOMING. SURFACE GRADIENT IS QUITE TIGHT WITH APPROX 15 MB OVERNIGHT BETWEEN KRKS AND KGCC. ALSO WILL SEE SOME 50KT+ AT H7. WILL UPGRADE HIGH WIND WATCH FROM 9 PM THROUGH 9AM...THOUGH CANCEL THE WATCH FOR WESTERN SWEETWATER AS THE BEST GRADIENT IS OFF TO THE EAST. THE WINDS DIMINISH BY LATE MORNING...THOUGH REMAIN BREEZY TO WINDY THROUGH THE DAY. NORTHWEST WINDS PICK UP FOR FRIDAY AND FRIDAY EVENING OVER MUCH OF THE AREA...AS THE SURFACE LOW LIFTS NORTHEAST INTO EASTERN MONTANA AND THE DAKOTAS. LIGHT SHOWERS LINGER THROUGH SATURDAY IN THE NORTHWEST FLOW WITHIN THE TROUGH AXIS. THE TROUGH AXIS WILL BE SLOW TO EXIT...NOT UNTIL SATURDAY NIGHT. FLAT RIDGING BUILDS IN BEHIND THE SLOWLY DEPARTING TROUGH. SOME CLOUDS LINGER THROUGH SUNDAY. TEMPERATURES RECOVER A BIT ON SATURDAY AND SUNDAY TO NEAR SEASONABLE NORMS. .LONG TERM...SUNDAY NIGHT THROUGH THURSDAY A SERIES OF SHORTWAVE TROUGHS WILL AFFECT THE REGION THROUGH THE EXTENDED PERIOD. A LOOK AT H5 HEIGHTS INDICATES A PERIOD OF SEASONAL TEMPERATURES AS ZONAL FLOW ALOFT DEVELOPS SUNDAY NIGHT AND EARLY MONDAY. AN UPPER LEVEL LOW PRESSURE SYSTEM OFF THE BRITISH COLUMBIA COAST WILL EJECT A SHORTWAVE INTO THE NORTHERN ROCKIES MONDAY AFTERNOON MAINLY AFFECTING THE WESTERN MOUNTAINS BRINGING A FEW RAIN SHOWERS BECOMING SNOW OVERNIGHT. SIGNIFICANT ACCUMULATION DOES NOT APPEAR LIKELY ATTM BUT THIS WILL BEAR WATCHING AS THE TIME APPROACHES. MID RANGE MODELS IS GOOD AGREEMENT ON BUILDING A STRONG RIDGE IN THE PACIFIC OFF THE CALIFORNIA COAST BY TUESDAY. THIS WILL KEEP THE MAIN STORM TRACK TO THE NORTH. HOWEVER THIS WILL ALSO TIGHTEN THE PRESSURE GRADIENT AS THE PARADE OF SHORTWAVES CONTINUE. TUESDAY NIGHT APPEARS TO BEGIN A WINDY PERIOD AS NORTHWEST FLOW DEVELOPS ON THE BACK SIDE OF THE RIDGE. A WAVE ON TUESDAY NIGHT SHOULD BRING A FEW SHOWERS TO THE NORTH AND SLIDE A COLD FRONT THROUGH THE CWA. WINDY CONDITIONS CAN BE EXPECTED TO ACCOMPANY THIS FRONT. CONFIDENCE IN FORECAST IS LOW BEYOND TUESDAY AS MODELS ARE TENDING TO DIVERGE A BIT WITH THE GFS FLATTENING OUT THE RIDGE A BIT ALLOWING COOLER AIR IN FROM THE NORTH. OTHER GUIDANCE KEEPING A MORE AMPLIFIED RIDGE THROUGH THURSDAY WHICH WOULD BRING DRIER AND WARMER CONDITIONS. .AVIATION.../00Z ISSUANCE/ WIDESPREAD MVFR/IFR CIGS AND VSBY EXPECTED WEST OF THE CONTINENTAL DIVIDE THROUGH 18Z FRIDAY. PERIODS OF SNOW AND LOW STRATUS WILL OBSCURE MOUNTAINS IN AREAS WEST OF THE CONTINENTAL DIVIDE. AS THE STORM DEVELOPS...STRONG AND GUSTY WIND WILL BEGIN ALONG THE SOUTHERN WIND CORRIDOR WITH THE KRKS-KCPR AREA EXPERIENCING SOUTHWEST WIND OF 25 TO 35 KT GUSTING TO NEAR 50 KT AT TIMES. SNOW AROUND THE BIGHORNS WILL ALSO BRING IFR CIGS/VSBY STARTING TONIGHT AS WELL. THE BIG HORN BASIN WILL SEE MAINLY RAIN WITH THE GREATEST IMPACT TO CIGS IN LOW STRATUS THROUGH 18Z FRIDAY. AFTER 18Z THE MAIN IMPACTS WILL BE IN THE BIGHORNS AND AROUND KBYG WITH RAIN AND POSSIBLY SNOW EXTENDING TOWARD KCPR. FIRE WEATHER... FIRST STORM OF THE SEASON WILL CONTINUE TO BRING SNOW TO THE WEST OVERNIGHT INTO FRIDAY MORNING. RAIN AND SNOW WILL SPREAD INTO THE NORTH AND EVENTUALLY INTO THE CENTRAL. WINTER WEATHER ADVISORIES ARE IN EFFECT FOR THE MUCH OF THE WEST WITH A WINTER STORM WARNING FOR THE BIGHORNS. SNOW LEVELS EAST OF THE DIVIDE WILL BE ABOVE 6500 TO 7000 FEET. THE PRECIPITATION WILL DIMINISH LATE FRIDAY MORNING INTO THE AFTERNOON WITH LINGERING SHOWERS EXPECTED THROUGH SATURDAY. HIGH WINDS ARE EXPECTED TONIGHT BETWEEN EASTERN SWEETWATER...SOUTHEAST FREMONT AND NATRONA COUNTIES. GUSTY NORTHWEST TO WEST WINDS CAN BE EXPECTED TONIGHT AND FRIDAY ACROSS MUCH OF THE REMAINDER OF THE AREA. && .RIW WATCHES/WARNINGS/ADVISORIES... HIGH WIND WARNING FROM 9 PM THIS EVENING TO 9 AM MDT FRIDAY WYZ019-020-030. WINTER WEATHER ADVISORY UNTIL 9 AM MDT FRIDAY WYZ001-012>015-023-024. WINTER WEATHER ADVISORY UNTIL NOON MDT FRIDAY WYZ002. WINTER STORM WARNING FROM 9 PM THIS EVENING TO NOON MDT FRIDAY WYZ008-009. && SHORT TERM...TWB LONG TERM...BERC AVIATION...BERC FIRE WEATHER...TWB
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE RIVERTON WY 355 PM MDT THU OCT 6 2011 WYZ001>020-022>030-071101- 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- 355 PM MDT THU OCT 6 2011 ...WINTER STORM WARNING FOR THE BIGHORN MOUNTAINS TONIGHT THROUGH NOON FRIDAY... ...HIGH WIND WARNING FROM ROCK SPRINGS TO JEFFERY CITY TO CASPER TONIGHT THROUGH FRIDAY MORNING... ...WINTER WEATHER ADVISORY FOR THE WESTERN MOUNTAINS AND VALLEYS THROUGH FRIDAY MORNING.... THIS HAZARDOUS WEATHER OUTLOOK IS FOR WESTERN AND CENTRAL WYOMING. .DAY ONE...TONIGHT SNOW WILL CONTINUE TONIGHT IN THE MOUNTAINS AND VALLEYS OF WESTERN WYOMING. SIGNIFICANT SNOWFALL IS LIKELY IN MUCH OF THESE AREAS. VERY STRONG SOUTHWEST WINDS OF 30 TO 40 MPH ALONG WITH GUSTS OF 60 MPH ARE POSSIBLE FROM ROCK SPRINGS TO JEFFREY CITY TO CASPER TONIGHT. .DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY FRIDAY...COLDER WITH A GOOD CHANCE OF RAIN AND MOUNTAIN SNOW ALONG WITH SNOW AT THE LOWER ELEVATIONS ALONG AND WEST OF THE DIVIDE THROUGH 9 AM. MODERATE TO HEAVY SNOW WILL DEVELOP ACROSS THE BIGHORN MOUNTAINS AND LAST THROUGHOUT THE DAY FRIDAY. SIGNIFICANT SNOWFALL IS LIKELY IN MUCH OF THESE AREAS. SNOW LEVELS COULD DROP AS LOW AS 5000 FEET ACROSS PORTIONS OF CENTRAL WYOMING. VERY STRONG SOUTHWEST WINDS OF 30 TO 40 MPH ALONG WITH GUSTS OF 60 MPH ARE POSSIBLE FROM ROCK SPRINGS TO JEFFREY CITY TO CASPER FRIDAY MORNING. .SPOTTER INFORMATION STATEMENT... SPOTTERS ARE ENCOURAGED TO REPORT SNOWFALL ACCUMULATIONS AS WELL AS ANY WIND GUSTS ABOVE 45 MPH. THANK YOU. TEAM RIVERTON
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 2011Every state in 2011This day in weather historyWarnings in Wyoming, October 2011
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: 350859, 350860.