A group of 6 snowboarders built a jump on a bank near Togwotee Pass. The first person to go off the jump triggered a slab avalanche that buried him 9 feet deep in the snow.
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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 group of 6 snowboarders built a jump on a bank near Togwotee Pass. The first person to go off the jump triggered a slab avalanche that buried him 9 feet deep in the snow. The man was wearing a transceiver and was eventually excavated. The man was given CPR but died at the scene.
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 18, 9:50 AM MST, 2 hours 10 minutes earlier.
Area Forecast Discussion National Weather Service Riverton WY 950 AM MST Thu Feb 18 2021 .SHORT TERM...(Today through Friday) Issued at 339 AM MST Thu Feb 18 2021 The broad central US trough will be shifting east today (finally), bringing a brief stop to snowfall across western and central WY. Main forecast issue today will be winds across central WY. Gradient tightening across the state will bring gustier winds from KRKS to KCPR and along the Absarokas. frequent gusts of 25 to 35kts can be expected this afternoon. The ridge will flatten starting tonight as a series of shortwaves races across the state. The first wave arrives just after midnight tonight, bringing a return of snowfall to the western mountains. Since this wave is moving quickly, accumulations will be brief, occurring mainly between midnight tonight and noon Friday. After this, the weaker northwest flow will continue to produce periods of light snow through the rest of the afternoon and evening before the next wave arrives late Friday night. The northwest flow aloft will help bring warmer temperatures to areas east of the divide Friday, with widespread 30s to near 40 degrees for most lower elevations. Gustier winds will return as well, with most higher elevations and Sweetwater County seeing gusts of 35 to 45 mph during the afternoon. .LONG TERM...(Friday night through Wednesday) Issued at 339 AM MST Thu Feb 18 2021 A subtle ridge briefly sets up to start the term; however, a decent Pacific shortwave trough pushes the ridge out by early Saturday morning. Models have been in disagreement with the placement of this trough. The ECMWF solution has seemed to win out as both the GFS and CMC have come into agreement with a more southerly tracking trough. Along with NW flow and the track of this trough snow appears to be confined to the western mountains and southern zones. Snow totals are still up in the air with the constantly evolving system and will be looking into potential hazard issuance. As the trough departs midday Sunday, NW flow sets up again and upslope snow continues in the western mountains. An elongated jetstreak positions itself north of the CWA which will allow warmer surface temperatures across the region. Tuesday sees model disagreement at its finest. The ECMWF brings a trough with widespread PoP late Tuesday. The GFS and CMC keep NW flow through early Wednesday. The CMC breaks with the GFS Wednesday morning and aligns more with the ECMWF. Needless to say, this is something to watch evolve and see which solution is going to win out for the end of the term. && .AVIATION...(For the 18Z TAFS through 18Z Friday afternoon) Issued at 926 AM MST Thu Feb 18 2021 East of the Divide...KCOD/KCPR/KLND/KRIW/KWRL Terminals The ongoing fog/low ceilings at KLND should be gone by around 18Z. Otherwise, VFR conditions are expected through the period with variable mid-high level cloudiness especially late tonight into Friday morning. Winds will be light today, but gusty southwest to west winds will develop late tonight at KCPR and probably KCOD. Those areas look to remain windy for the remainder of the TAF period. West of the Divide...KBPI/KJAC/KPNA/KRKS Terminals Ongoing flurries and low ceilings over the far west are expected to improve between 18Z to 20Z. VFR conditions are then expected through at least 03Z Friday. However there will likely be ceilings between 4 and 6 kft agl over the west. KRKS will have windy westerly flow this afternoon, before weakening a bit overnight, but those strong winds return Friday morning. After 06Z, another storm system will bring widespread snow across the west. The snow will last through about 18Z Friday, before decreasing in areal coverage and intensity. KJAC will be most impacted with IFR conditions likely late tonight into Friday morning, before improving gradually Friday afternoon. Farther southeast into the Upper Green River Basin (KBPI and KPNA) the snow looks to be more showery in nature and confidence is not high enough to prevail MVFR or IFR conditions at this time. KRKS will be dry, but windy. 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 339 AM MST Thu Feb 18 2021 Gusty winds return to southern and central WY today, with gusts of 25 to 30 expected today, and 30 to 40 mph on Friday. Friday will also see gustier winds into the Absarokas. This will help with improved mixing across the state. Snowfall returns to the western mountains tonight, and will continue through Saturday. && .RIW WATCHES/WARNINGS/ADVISORIES...NONE. && SHORT TERM...Straub LONG TERM...Vorst AVIATION...Murrell FIRE WEATHER...Straub
Hazardous Weather Outlook National Weather Service Riverton WY 252 AM MST Thu Feb 18 2021 WYZ001>020-022>030-191000- 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- 252 AM MST Thu Feb 18 2021 This Hazardous Weather Outlook is for Western and Central Wyoming. .DAY ONE...Today and Tonight. No hazardous weather is expected at this time. .DAYS TWO THROUGH SEVEN...Friday through Monday. Friday through Sunday, expect a chance of snow over the west, spreading east through the weekend. Windy conditions expected across the usual Wind Corridor. .SPOTTER INFORMATION STATEMENT... Spotter activation will not be needed.
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 | 2021-02-18 | 31 | 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: 940635.