An extended period of Pacific moisture influx brought large amounts of moisture into southeast Idaho with continuous periods of light to moderate snowfall occasional strong winds. The entire region was under advisories and warnings for the entire week overlapping the Christmas holiday.
Every event with a place to put it; 15 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 PIH wrote it up.
An extended period of Pacific moisture influx brought large amounts of moisture into southeast Idaho with continuous periods of light to moderate snowfall occasional strong winds. The entire region was under advisories and warnings for the entire week overlapping the Christmas holiday. Several roads closed on the 26th with heavy snow amounts and strong winds.
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 22, 7:47 AM MST, 13 minutes earlier.
Area Forecast Discussion National Weather Service Pocatello ID 747 AM MST Wed Dec 22 2021 .SHORT TERM (Today - Thursday)...Quick update this morning to increase snow potential across the CNTRL mountains as we are already accumulating snow in the Stanley Basin. See previous discussion below. Huston Today is the day that high pressure will gradually give way to a prolonged period of U/L troughiness across the Pacific NW. An unsettled weather pattern will then setup across our area through the Christmas holiday and likely continuing into early next week. Shortwave trough moving towards Vancouver Island will help bring Pacific moisture into the region. Central Mountains should see this moisture influx begin around daybreak before it gradually moves across the rest of the area into the afternoon. Hi-res models show activity will be scattered in nature but nevertheless do have PoPs in the forecast across all of eastern Idaho. Snow should be the dominant precip type although we could see a brief rain/snow mix in the eastern Magic Valley. As we move into Thursday, moisture becomes more enhanced over all of Idaho and thusly we can expect more widespread coverage of snow along with some decent accumulations. Winter Storm Watches remain in place across our higher terrain zones and these will likely become warnings on the next forecast package. Elsewhere, light accumulations can be expected with 1-2 inches likely in the Snake Plain. Temperature profiles may support a brief rain/snow mix in the afternoon from around Pocatello into Burley which would help limit accumulations in town although the benches would still likely see all snow. The snow machine doesn't look to slow down anytime soon as we move towards Christmas...more on that below. McKaughan .LONG TERM (Christmas Eve through next Wednesday)... A series of disturbances will drive into the PAC NW from the Gulf of Alaska through the extended period. These disturbances will help establish and maintain a long wave trough over the western states through the forecast period. The long-term periods look to be quite unsettled as a result. The first round of snow should be well underway on Christmas Eve as an upper low drops into Vancouver Island Friday morning. This low will kick out a shortwave trough through the area in the afternoon. We get a slight break on Saturday, though some snow may continue in the mountains. The low should fill slightly and start to progress eastward on Sunday, bringing another round of moderate to heavy snow to the area. Upper troughs on Monday and Wednesday will target much of the region with snow, though models start to show some differences in timing and intensity. The overall theme for the long-term is snowy and becoming colder with each passing wave. The year appears to be concluding on a cold and wet note. This will be good in building up a robust snow pack, but not very favorable for holiday travel. Hinsberger && .AVIATION... Upper ridge axis will shift east this morning, allowing a return of Pacific moisture to the region. Precip should begin in the Sun Valley area around mid to late morning with ceiling and visibility dropping throughout the day below VFR as snow rolls in. Some models suggest KSUN will drop to MVFR and some to IFR. HREF suggests a brief possibility of LIFR conditions early in the TAF period, and again late tonight. Downslope winds setting up late this morning and afternoon should keep VFR conditions with low precip chances at BYI, IDA and PIH. DIJ may also see some downslope winds this afternoon, but may see ceilings drop MVFR late tonight with a slight chance of snow. Hinsberger && .AIR STAGNATION... Inversions have led to worsening air quality in some areas of eastern Idaho. We should see those inversions weaken Wednesday. Conditions have deteriorated enough in Franklin County for an Air Quality Advisory. && .PIH WATCHES/WARNINGS/ADVISORIES... Winter Storm Watch from late tonight through Friday afternoon for IDZ063-064-066. Winter Storm Watch from this evening through Thursday evening for IDZ071>075. Winter Storm Watch from Thursday morning through Friday afternoon for IDZ060. &&
The national radar mosaic for the moment the first event began.
13 winter storm, 1 winter weather, 1 heavy snow. Local standard time, as filed.
An extended period of snow and wind closed US Highway 93 from Arco to Carey on December 26th. Snow amounts in the extended period ranged from 2 to 10 inches.
An extended period of Pacific moisture influx created high winds and snow over the several days surrounding the Christmas Holiday. 6 inches of snow fell in Dubois. Interstate 15 was closed from Dubois to the Montana border on December 26th.
Several days of strong Pacific moisture influx brought heavy snow with periods of very strong winds over a 6 day period surrounding the Christmas holiday. Travel was very difficult with Idaho Highway 34 closed from Soda Springs to the Wyoming border. Soda Springs recorded 19 inches of snow and Bone recorded 14 inches of snow.
A long period of Pacific moisture streamed into the region with strong winds and heavy snow. Idaho highway 34 was closed from Soda Springs to the Wyoming border on the 26th and US Highway 26 was closed from Ririe to Swan Valley. At least 60 motorists were stranded in Swan Valley on the 26th due to the road closure. Swan Valley received 7 inches of snow.
A long period of snow and and periods of strong winds over several days surrounding the Christmas holiday brought extreme travel difficulties. Idaho Highway 47 from Ashton to Warm River, Idaho Highway 87 from Island Park to the Montana border, US Highway from Ashton to the Montana border were all closed on December 26th. The Island Park COOP observer recorded 24 inches of snow from the 24th through 27th.
An extensive period of Pacific moisture influx caused periods of snow combined with strong winds to create very difficult travel conditions over several days surrounding the Christmas holiday . The Chilly Barton Flat COOP site measured 8 inches of snow on the 26th and 27th. US Highway 93 was closed from Carey to Arco on the 26th.
Heavy snow fell with 11 inches in Inkom and 14 inches at Downey measured by the COOP observers. 17.5 inches was measured by the Cocorahs observer 3 miles north northwest of Lava Hot Springs.
An extended period of Pacific moisture pushing into Idaho caused snow and periods of strong winds over and extended period covering the Christmas holiday. The Richfield COOP observer reported 11 inches of snow with US Highway 93 closed from Carey to Arco on the 26th.
The COOP observer measured 21 inches of snow at the Ketchum site over the 24th through 27th.
Ten inches of snow was measured 3 miles north northeast of Driggs. On the 26th US Highways 20 was closed from Ashton to the Montana border. Idaho Highway 32 was closed from Ashton to Tetonia. Idaho Highway 33 was closed from Newdale to Tetonia.
Extremely heavy snow fell in the Wood River Foothills. Amounts recorded were the following: Bellevue 25 inches, Hailey 23 inches, Picabo 21 inches.
A long period of heavy snow and strong winds occurred in the Big Hole's. Idaho Highway 33 was closed at Teton Pass on the 26th. High elevations reported over a foot of snow.
The COOP observer in Bern recorded 15 inches of snow with 12 inches on the 25th and 26th.
A long period of snow and occasional strong winds surrounding the Christmas holiday brought difficult travel to the region. Idaho Highway 33 was closed from Newdale to Tetonia. US Highway 26 was closed from Ririe to Swan Valley. The Idaho Falls COOP observer recorded 11 inches of snow from the 23rd to 27th. 9.4 inches fell in St Anthony.
Heavy snow and strong winds occurred over an extended period in the days surrounding the Christmas holiday. The COOP observer at Minidoka measured 8 inches of snow with 6 on the 25th and 26th. The Oakley COOP observer carried 16 inches of snow from the 25th through 27th.
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: 999843, 999895, 999898, 999900, 999901, 999906, 999907, 999908, 999912, 999914, 999919, 999897, 999896, 999916, 999905.