A 33 year old snowboarder was riding down steep terrain in the Tetons. He triggered an avalanche that carried the snowboarder over a 50 foot cliff into steep and rocky, terrain, He did not survive the fall.
Every event with a place to put it; 1 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 33 year old snowboarder was riding down steep terrain in the Tetons. He triggered an avalanche that carried the snowboarder over a 50 foot cliff into steep and rocky, terrain, He did not survive the fall.
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 Feb 22, 10:26 AM MST, 1 hour 34 minutes earlier.
Area Forecast Discussion National Weather Service Riverton WY 1026 AM MST Mon Feb 22 2021 .SHORT TERM...Today through Tuesday The main challenge today will continue to be strong to high winds. Favorable weather parameters remain in place for a high wind event. The right-exit region of a 140 kt upper jet will remain over the forecast area today. At 700 mb, there is a tight isohypse gradient of 100 to 120 decameters, from southwest to northeast, across the Cowboy State with winds of 40 to 60 kts. No changes to already issued High Wind Warnings. Upgraded the High Wind Watch for Natrona County to a Warning, with signs still pointing for high winds to occur there today. There could be a brief lull tonight there, but wind speeds will only be slightly lower than criteria. A couple of points of interest; the winds over the Absaroka Mountains and Cody Foothills will remain gusty this afternoon and tonight, after the warning expires. However, high winds could return tonight in response to the approaching cold front. Also, winds look to weaken and decouple over the Wind River Basin this evening. However, another High Wind Warning may be needed Tuesday. High winds look to return late Tuesday morning through the rest of the day as the cold front moves through the area, with strong winds continuing through the afternoon in the wake of the front. Above average highs will occur again east of the Divide today, due to the wind. Light snow/flurries will develop over the northwest this afternoon, with snow becoming likely before midnight. Most of the snow activity tonight will be confined along and north of an Alpine-to-Dubois line. Moderate, with periods of heavy, snow will occur late tonight through Tuesday morning. Strong winds will occur with the snow as well, with winds 30 to 40 mph gusting up to 55 mph possible. Have issued a Winter Weather Advisory, as a result. Localized amounts up to 12 inches expected in the Tetons. The cold front will quickly move across the forecast area Tuesday morning, clearing areas east of the Divide by midday. The best chances of snow will occur across portions of Johnson and Natrona counties after daybreak, but will end by noon as the front continues its fast pace toward the southeast. Little to no accumulation is expected at this time. .LONG TERM...Tuesday night through Sunday Looking to the long-term period, expect below normal temperatures for most locations throughout the forecast period. After a fairly mild Tuesday in most places, expect temperatures to take quite a drop for Tuesday night with some lingering areas of snow across the state. Chances for snow will be possible across areas west of the Divide, as an upper low moves over eastern ID/northern UT. By Wednesday night into early Thursday, the precipitation is projected to be confined mainly to CO. During the day Thursday, a transitory ridge moves over the state keeping it mainly dry. This looks to be short-lived, as a trough is forecasted to be near the OR/ID border by 00Z Friday with some precipitation moving into the northwest again. The trough looks to move through the CWA during the day Friday with more precipitation. Most of the activity again looks to be confined to areas west of the Divide. Saturday looks to have more widespread coverage across the state, with a strong trough sliding across the area. Confidence is low going into Sunday, but the consensus seems to have the moisture moving out of the area early in the day, with the possible exception of the area around YNP. && .AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon) Issued at 1025 AM MST Mon Feb 22 2021 East of the Divide...KCOD/KCPR/KLND/KRIW/KWRL Terminals All sites are expected to be VFR through the TAF period. Winds will be the biggest impacts across the area as all terminals are expected to be windy. The windiest being KCPR with gusts upwards of 40kts. LLWS is possible at KCOD but confidence wasn't high enough to have included it the TAF. West of the Divide...KBPI/KJAC/KPNA/KRKS Terminals All sites with the exception of KJAC are expected to be VFR. KJAC could experience some MVFR/IFR visibilities as snow continues to impact that site through the TAF period. Wind will be the biggest impact to the other terminals. LLWS is possible at the remaining sites and is included in the TAF at KBPI and KPNA; however, confidence wasn't high enough to include it at KRKS. Nonetheless, KRKS will be the windiest with gusts approaching 45kts. Please see the Aviation Weather Center and/or CWSU ZDV and ZLC for the latest information on icing and turbulence forecasts. && .FIRE WEATHER... Strong winds will remain to be the main concern today, impacting zones 276, 277, 279, 280, 283, 286, 288, 289 today through at least Tuesday. In these areas, smoke dispersal will be good. Elsewhere, smoke dispersal will be poor to possibly fair. Snow will redevelop tonight over the northwest and continue through Tuesday morning. The rest of the area will remain dry. && .RIW WATCHES/WARNINGS/ADVISORIES... High Wind Warning until noon MST today for WYZ002-003. High Wind Warning until 5 PM MST this afternoon for WYZ016-017- 030. High Wind Warning until noon MST Tuesday for WYZ020. Winter Weather Advisory from 11 PM this evening to noon MST Tuesday for WYZ012-013. && SHORT TERM...LaVoie LONG TERM...Clayton AVIATION...Vorst FIRE WEATHER...LaVoie
Hazardous Weather Outlook National Weather Service Riverton WY 321 AM MST Mon Feb 22 2021 WYZ001>020-022>030-231030- 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- 321 AM MST Mon Feb 22 2021 ...Multiple High Wind Warnings are in effect for areas east of the Divide and over the south Today... ...Winter Weather Advisory in effect for portions of Teton County tonight into Tuesday... This Hazardous Weather Outlook is for Western and Central Wyoming. .DAY ONE...Today and Tonight. Strong to high wind across the Cody Foothills, Absaroka Mountains, Wind River Basin, Natrona County and eastern Sweetwater County. Please see the high wind statement for further details. Significant snow and blowing snow over the far west and northwest tonight. .DAYS TWO THROUGH SEVEN...Tuesday through Sunday. Tuesday...Significant snow and blowing snow over the far west and northwest through the morning. Widespread gusty winds, as a cold front moves through the area. Strong to high winds possible again in the Wind River Basin. Friday...Another round of snow is expected over the west. .SPOTTER INFORMATION STATEMENT... Weather spotters are encouraged to report significant winter weather conditions, according to standard operating procedures. Team Riverton
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE RIVERTON WY
619 AM MST MON FEB 22 2021
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0546 PM NON-TSTM WND GST ROCK SPRINGS 41.60N 109.22W
02/21/2021 M60 MPH SWEETWATER WY ASOS
&&
TLPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE RIVERTON WY
921 AM MST MON FEB 22 2021
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0912 AM NON-TSTM WND GST 8 E SUNLIGHT BASIN 44.74N 109.38W
02/22/2021 M83 MPH PARK WY MESONET
MESONET STATION KCHJ SUNLIGHT BASIN 8 E
(WYDOT).
0906 AM NON-TSTM WND GST 12 NNW BUFFALO 44.51N 106.80W
02/22/2021 M63 MPH JOHNSON WY MESONET
MESONET STATION WY53 STORY 6 SE (WYDOT).
0853 AM NON-TSTM WND GST 3 NNW BUFFALO 44.38N 106.72W
02/22/2021 M61 MPH JOHNSON WY ASOS
ASOS STATION KBYG BUFFALO AIRPORT.
&&The national radar mosaic for the moment the first event began.
1 avalanche. Local standard time, as filed.
Please see episode narrative for details.
As the offices recorded each death: direct deaths were caused by the weather itself, indirect ones by something it set in motion.
| Event | Date | Age | Sex | Where | Kind |
|---|---|---|---|---|---|
| Avalanche, Teton & Gros Ventre Mountains | 2021-02-22 | 33 | Male | Outside/Open Areas | Direct |
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, February 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: 940636.