A cold front and trough moved across Wyoming and brought high winds to portions of central Wyoming. The highest wind gust reported was 79 mph at Crowheart.
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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.
A cold front and trough moved across Wyoming and brought high winds to portions of central Wyoming. The highest wind gust reported was 79 mph at Crowheart. Along Wyoming Boulevard south of Casper, several 65 mph wind gusts were registered.
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 24, 10:30 PM MST, 2 hours 6 minutes earlier.
Area Forecast Discussion National Weather Service Riverton WY 1130 PM MDT Sun Oct 24 2021 .SHORT TERM...(This evening through Tuesday) Issued at 230 PM MDT Sun Oct 24 2021 Weak upper-level ridging will continue through the day but with increasing moisture aloft and a few small perturbations in the flow, cloud cover will increase this evening. Lower elevation rain and mountain snow showers increase over far western zones this evening through the overnight. Potent southwesterly flow takes over Monday after the weak ridge breaks down tonight. Increasing likelihood for high winds and widespread rain and mountain snow showers exist for Monday. With the afternoon package, upgraded the High Wind Watch to a High Wind Warning and issued Winter Weather Advisories for the Wind River, Teton, and Gros Ventre mountain ranges. Sustained wind of 25 to 35 mph with gusts from 50 to 60 mph are expected in the warned area. Impacts to Interstates 80 and 25 can be expected especially with high profile vehicles. Also have issued Special Weather Statements for strong winds in the Wind River and Absaroka mountains since the southwesterly flow will promote downsloping on the leeside of the ranges. As for the Winter Weather Advisories, upslope coupled with ample moisture will favor accumulating snow of 3 to 6 inches over western Wyoming mountain passes, and 6 to 12 inches for the highest peaks. The overall system is expected to impact the western mountains early Monday morning and continue through the day. The cold front will eventually drag across the divide, late Monday night into Tuesday spreading PoP into the eastern zones. Temperatures were a little difficult but due to the southwesterly flow, opted for a slightly warmer solution due to the WAA. With the slightly warmer solution, snow levels look to remain in the 7000 to 8000 ft range when the majority of the moisture moves through. Some lingering isolated snow showers may be possible Tuesday night as CAA behind the front allows for shallow instability aloft. .LONG TERM...(Wednesday through Sunday) Issued at 230 PM MDT Sun Oct 24 2021 The deep trough that brought winds and widespread precipitation to the area early in the week will begin to shift east of the region by Tuesday night. A strong jet on the backside of the trough will position robust northwesterly flow over Wyoming through the day Wednesday. Upslope mountain-based snow showers continue, with light accumulations over the western Wyoming ranges. Winds Wednesday afternoon will again be breezy from the west and northwest, gusting 35 to 40 mph as a surface high over the Great Basin moves eastward. Temperatures look to be near seasonal averages, with mid 50s east of the Divide and low 40s west of the Divide. The jet exits eastward overnight into the day Thursday, with a building longwave ridge over the western CONUS. This pattern holds through Friday, and is likely to bring pleasant autumn weather including: above average warmth, mostly sunny skies, and relatively light winds. Models begin to diverge over the weekend. The consistent feature is a longwave trough over Canada that begins to suppress the ridge. This results in lowering heights and a return of near normal temperatures. A shortwave feature originating over the Pacific moves ashore Saturday, with the EC maintaining a more northerly track for this smaller wave. If this northerly track is correct, this could bring light rain/snow showers to our area on Sunday. Will continue to monitor this timeframe, but for now, have opted to stick with consensus guidance that splits the difference. && .AVIATION...(For the 06Z TAFS through 06Z Monday Evening) Issued at 1130 PM MDT Sun Oct 24 2021 West of the Divide...KBPI/KJAC/KPNA/KRKS Terminals Low-end VFR ceilings and scattered light rain showers linger at KJAC and northwest Wyoming until around sunrise Monday. Brief periods of MVFR possible at KJAC during this time. Otherwise, VFR prevails into the afternoon before moisture returns to KJAC just prior to 00Z/Tuesday. Showers become more widespread Tuesday evening and spread to KBPI and KPNA around 06Z/Tuesday. Mountain tops frequently obscured through the period. Pre-frontal southerly surface wind to occur at all terminals during the daylight hours. KRKS tops out with surface speeds 25-35 kts with little decrease after sunset as a cold front approaches. Other terminals will see the nocturnal wind decrease in speed. East of the Divide...KCOD/KCPR/KLND/KRIW/KWRL Terminals VFR to prevail at all terminals through 06Z/Tuesday. Wind is the primary hazard for Monday with south to southwest wind steadily increasing during the morning and early afternoon. Wind shear in the 013-020 AGL layer possible at KCPR and KLND where forecast soundings show 40-50 kt winds. KCPR to top out with 25-40 kt surface speeds during the midday hours before decreasing around 00Z/Tuesday. Mid and high cloud decks increase and slowly fall during the evening. Please see the Aviation Weather Center and/or CWSU ZDV and ZLC for the latest information on icing and turbulence forecasts. && .FIRE WEATHER... Issued AT 230 PM MDT Sun Oct 24 2021 Active weather is forecast for the first half of the week. Cloud cover will increase this evening and overnight as widespread rain/snow showers develop over the mountains of western Wyoming. Downslope winds are likely in the high terrain and foothills on the northeastern slopes of the Absaroka, Wind River, and the central Bighorn Mountains overnight into Monday morning. Snow showers continue Monday for the western mountains. Monday afternoon will be warm and windy east of the Divide, with afternoon gusts 45 to 60 mph likely in the mountains and in lower elevations of the south central and central portions of the state (Casper Dispatch area). RHs drop into the 30 to 40 percent range Monday afternoon in concert with these high winds. Widespread light rain/snow showers are forecast for Tuesday, with increased afternoon RHs. Wednesday will again be windy, with a less active ridging pattern on Thursday and Friday. && .RIW WATCHES/WARNINGS/ADVISORIES... High Wind Warning from 9 AM to 9 PM MDT Monday for WYZ019-020- 030. Winter Weather Advisory from 6 PM Monday to noon MDT Tuesday for WYZ012-014-015. && SHORT TERM...Vorst LONG TERM...VandenBoogart AVIATION...CNJ FIRE WEATHER...VandenBoogart
Hazardous Weather Outlook National Weather Service Riverton WY 631 PM MDT Sun Oct 24 2021 WYZ001>020-022>030-251300- Yellowstone National Park-Absaroka Mountains-Cody Foothills- North Big Horn Basin-Southwest Big Horn Basin- Southeast Big Horn Basin-Owl Creek and Bridger Mountains- Bighorn Mountains West-Bighorn Mountains Southeast- Northeast Johnson County-Southeast Johnson County- Teton and Gros Ventre Mountains-Jackson Hole- Wind River Mountains West-Wind River Mountains East- Upper Wind River Basin-Wind River Basin-Lander Foothills- Green Mountains and Rattlesnake Range- Natrona County Lower Elevations-Casper Mountain-Star Valley- Salt River and Wyoming Ranges-Upper Green River Basin Foothills- Upper Green River Basin-South Lincoln County- Rock Springs and Green River-Flaming Gorge-East Sweetwater County- 631 PM MDT Sun Oct 24 2021 ...High Wind Warning Monday for Portions of Central and South- Central Wyoming... ...Winter Weather Advisory 6 PM Monday through 12 Noon Tuesday for the Teton, Gros Ventre and Wind River Mountains... This Hazardous Weather Outlook is for Western and Central Wyoming. .DAY ONE...Tonight The probability for widespread hazardous weather is low. .DAYS TWO THROUGH SEVEN...Monday through Saturday Monday...Strong wind gusts of 40 to 60 mph are likely in the wind corridor from near Rock Springs to Casper. The foothills above Lander could see similar speeds. Gusts of 30 to 40 mph will be common at many other locations. Monday night and Tuesday...Several inches of snow will fall in the western mountains, with the heaviest amounts falling during the nighttime hours. Wednesday...Gusty west wind gusts of 30 to 40 mph likely across a wide region. .SPOTTER INFORMATION STATEMENT... Spotter activation will not be needed tonight.
The national radar mosaic for the moment the first event began.
2 high wind. Local standard time, as filed.
A maximum wind gust of 65 mph was recorded along Wyoming Boulevard to the south of Casper.
A peak wind gust of 79 mph was recorded at Crowheart.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Wyoming in 2021Every state in 2021This day in weather historyWarnings in Wyoming, October 2021
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: 989172, 989171.