An avalanche near Driggs and Relay Ridge killed two teenage boys at around 2:45 PM on December 17th. It was in a backcountry area with one snow mobiler and one skier killed in the avalanche.
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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 PIH wrote it up.
An avalanche near Driggs and Relay Ridge killed two teenage boys at around 2:45 PM on December 17th. It was in a backcountry area with one snow mobiler and one skier killed in the avalanche.
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 Pocatello, ID wrote its last area forecast discussion before the first event at Dec 17, 2:02 PM MST, 18 minutes earlier.
Area Forecast Discussion National Weather Service Pocatello ID 202 PM MST Fri Dec 17 2021 .SHORT TERM...Tonight through Saturday night. Our busy week is about to get a little less busy. Last of the snow showers should dissipate this evening. Expect skies to clear, for a time. Lots of low level moisture is in place and winds will weaken overnight, so we'll probably see patchy fog and low stratus develop during the late evening and overnight hours. Some places could be rather dense, especially around Ashton/Island Park where models have been consistently pegging those areas. Saturday looks fairly quiet as a weak system presses into the region. There's a slight chance of some light snow across the Sawtooth region and the Island Park areas, but as a whole shouldn't produce significant impacts. 13 .LONG TERM...(Sunday - Friday)... The latter half of the weekend starts with a generally flat upper level ridge in place across the area. Some moisture looks to stream into the Pac NW on the northern periphery of the aforementioned ridge and may allow for a bit of precip across the higher terrain of the Central Mountains and along the Continental Divide. In this scenario, QPF would be very limited as the best moisture looks to be well north of our area so overall impacts in our area would be very limited. Ridge looks to amplify somewhat Monday and Tuesday pushing the plume of moisture up into Washington and the Idaho panhandle keeping our portion of the state dry. Things change as we get into Wednesday though as it appears our next weather system across the Pacific moves towards the western U.S during mid-week. GFS/ECMWF remain in disagreement with respect to timing and location of this system so this period of the forecast relied solely on the NBM guidance given the widely differing model solutions. Needless to say, not much confidence in the forecast during this particular time period. Nevertheless, signs are there to indicate that a more unsettled weather pattern looks to become established during the latter portion of next week potentially setting the stage for a snowy Christmas weekend. Time will tell. McKaughan && .AVIATION...Still seeing lingering cloud cover across portions of the Snake Plain keeping MVFR cigs in place at KPIH. Model guidance shows ample low-level moisture in place across the region with hints of maybe some low stratus/fog potential at KPIH, KIDA and KDIJ. Confidence isn't overly high with this development but given fresh snowpack, certainly seems plausible. That being said, have BR forecast in these places but without significant restrictions in place for the present time. If low clouds are realized, they would likely linger into the latter portions of the TAF period. McKaughan && .PIH WATCHES/WARNINGS/ADVISORIES... None. &&
The national radar mosaic for the moment the first event began.
1 avalanche. Local standard time, as filed.
An avalanche near Driggs and Relay Ridge killed two teenage boys at around 2:45 PM on December 17th. It was in a backcountry area with one snow mobiler and one skier killed in the avalanche.
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, Big Hole Mountains | 2021-12-17 | 17 | Male | Outside/Open Areas | Direct |
| Avalanche, Big Hole Mountains | 2021-12-17 | 17 | Male | Outside/Open Areas | Direct |
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Idaho in 2021Every state in 2021This day in weather historyWarnings in Idaho, December 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: 999690.