Winter Storm and Avalanche in Idaho, February 20 to 23, 2023

Name: Winter Storm and Avalanche in Idaho, February 20 to 23, 2023
Start: 2023-02-20T00:00
End: 2023-02-23T20:00
Location: Idaho

February 20 to 23, 2023 · NWS PIH · 17 events in 15 counties and zones

Another Pacific storm system brought another year of strong winds, heavy snow with road closures, hazardous travel and school closings.

Where it happened

Every event with a place to put it; 17 filed by county or forecast zone are drawn at its center, in a lighter ring. Tap one for its entry below.

Tornadoes
Tropical storms and surge
Floods
Wind
Hail
Winter weather
Heat and drought
Cold
Fire, smoke and dust
Marine and coastal
Other

Open the live radar over this ground

The toll

Deaths: 0
Injuries: 0
Property damage: None recorded
Crop damage: None recorded
Events: 17

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.

What happened

The episode as NWS PIH wrote it up.

Another Pacific storm system brought another year of strong winds, heavy snow with road closures, hazardous travel and school closings.

What forecasters said that day

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 Feb 19, 9:09 PM MST, 2 hours 51 minutes earlier.

Area forecast discussion, Feb 19, 9:09 PM MST, 2 hours 51 minutes before

Area Forecast Discussion
National Weather Service Pocatello ID
909 PM MST Sun Feb 19 2023

.UPDATE...A quick forecast update this evening to thin out some
overnight snow amounts especially outside of the Sawtooths and
eastern highlands. We MAY see some light snow and flurries along
the I-15 corridor from Idaho Falls to around Pocatello, but it is
dry out there and flurries may be all we get, if that. We are also
expecting downslope to hold from around Pocatello west and south.
This should keep temperatures at or above freezing in those areas,
and also eat away at the snowpack that is out there...which could
impact blowing/drifting potential ahead of the main snow push for
these areas later tomorrow and Tuesday.  Keyes

&&

.PREV DISCUSSION... /issued 247 PM MST Sun Feb 19 2023/

SHORT TERM...Tonight through Tuesday night. Very complex
pattern arrives for the short term. Tonight through Monday, flow
aloft remains northwesterly, with upslope enhanced light snows
redeveloping and then continuing for higher elevations. Winter Storm
Watches for the eastern highlands areas have been upgraded to Winter
Storm Warnings, not so much for snow over the next 24 hours, but as
a lead-in for the major shift in the pattern coming Monday night
into Tuesday.

Vigorous shortwave slides through the Gulf of Alaska into the PacNW
late Monday, introducing deep atmospheric moisture into East Idaho
by Monday night. Flow shifts more westerly, allowing for a few light
snow showers to impact the I-15 corridor. Lower elevation
temperatures to begin warming above freezing late in the day,
especially for areas without significant snow pack, generally
Eastern Magic Valley, Lower Snake Plain, and valley areas south of
the I-86 corridor. Moisture deepens drastically overnight Monday
night into Tuesday, along with arrival of strong mid-level 700mb
flow and steepening surface pressure gradient. Temperatures look to
remain fairly steady into the overnight hours, with lows not too far
off Monday's highs. Winds increase to near/above 30 mph for most of
East Idaho, with strong potential for gusts over 50 mph. For Eastern
Magic Valley and Lower Snake River Plain, where temperatures should
have decimated any existing snow pack, a Wind Advisory will likely
be needed. Further north into the Arco Desert and Upper Snake Plain
where deeper snow pack exists and temperatures remain cold enough, a
Winter Storm Watch has been issued for the strong winds and
potential for significantly reduced visibilities in blowing snow.
Areas of whiteout to near-blizzard conditions will be possible where
winds are the strongest, likely impacting US-20/US-26, portions of I-
15 north of Blackfoot, and SH-33 between Rexburg and Driggs. Heavier
snowfall across the Sawtooths, Sun Valley, southern Sawtooth, and
Raft River areas, along with winds at higher elevations, also
support issuance of Winter Storm Watch.

Arctic front dives through East Idaho roughly mid-day Tuesday.
Daytime highs are likely to be reached before noon, with
temperatures falling behind the front. Front does have some
instability associated with it, so there is potential for squalls as
the front drives through, with snowfall finally reaching the surface
in previously dry areas through the main travel corridors. Winds
gradually diminish behind the front as northerly flow descends into
East Idaho, except where northerly gap winds can remain gusty into
Tuesday night. Cold temperatures Tuesday night could be cold enough
to support Wind Chill Warnings especially for northern zones.
DMH

LONG TERM...Wednesday through next Sunday.
As the slow-moving upper low continues to descend further south,
models show a closed low forming over southern Idaho Wednesday.
Upslope flow will allow for additional light snow accumulations
across the eastern highlands through Friday as the low continues to
rotate south along the west coast. The greatest accumulations are
expected prior to sunrise Thursday and will be realized across the
Bear River and Caribou ranges. Winds will continue to taper off
throughout the day Wednesday, becoming generally light through the
remainder of the extended. Temperatures will gradually rise each day
throughout the long-term period, with lows across the lower Snake
Plain and Magic Valley in the 20s and highs reaching into the upper
30s and low 40s by Sunday. Cropp

AVIATION...
Predominately VFR conditions currently at all terminals with the
exception of KIDA, where CIGS have generally remained MVFR or worse.
 Winds will remain elevated and continue to strengthen over the next
couple of days, with winds reaching up to 20 mph everywhere except
KSUN through late tomorrow morning before peaking during the day
Tuesday. CIGs and VIS will begin to degrade by mid-morning Monday as
precipitation overspreads the region. Precipitation will begin as
rain everywhere except KSUN and KDIJ Monday through early Tuesday.
Cropp

&&

.PIH WATCHES/WARNINGS/ADVISORIES...
Winter Storm Watch from Monday evening through Tuesday afternoon
for IDZ052-053-056-057-071>074.

Winter Storm Warning until 5 AM MST Wednesday for IDZ058-060-062-
063.

Winter Storm Warning until 5 AM MST Wednesday for IDZ064>066.

&&

The radar

The national radar mosaic for the moment the first event began.

Open the radar archive at this moment

Event by event

9 winter storm, 6 heavy snow, 1 winter weather, 1 avalanche. Local standard time, as filed.

Winter Storm, Teton Valley

When: February 20, 12:00 AM MST to February 23, 8:00 PM MST
Where: Teton Valley forecast zone
Reported by: Department of Highways
Coordinates: 43.924, -111.450 (the zone’s center; the record gives no point)

Heavy snow and wind gusts over 40 mph shut down US Highway 20 from Ashton to the Montana border and Highway 87 from US 20 to the Montana border. State Highway 33 was closed from Newdale to Tetonia. State Highway 32 was closed from Ashton to Tetonia. Highway 47 was closed from Ashton to bear Gulch. Teton County School district 401 was closed on the 21st and 22nd due to hazardous and closed road conditions. North Fremont High School and Ashton Elementary School also closed on the 21st and 22nd. 4 to 8 inches of snow fell over the extended period.

Winter Storm, Centennial Mountains-Island Park

When: February 20, 12:00 AM MST to February 23, 8:00 PM MST
Where: Centennial Mountains-Island Park forecast zone
Reported by: Department of Highways
Coordinates: 44.091, -111.680 (the zone’s center; the record gives no point)

Heavy snow and wind gusts over 40 mph shut down US Highway 20 from Ashton to the Montana border and Highway 87 from US 20 to the Montana border. Highway 47 was closed from Ashton to Bear Gulch. North Fremont High School and Ashton Elementary School also closed on the 21st and 22nd. The Island Park COOP site recorded 11.7 inches of snow with the storm.

Winter Storm, Marsh and Arbon Highlands

When: February 20, 12:00 AM MST to February 23, 12:00 PM MST
Where: Marsh and Arbon Highlands forecast zone
Reported by: SNOTEL
Coordinates: 42.838, -112.256 (the zone’s center; the record gives no point)

Heavy snow fell over an extended period with COOP sites at Inkom and McCammon measuring 7 inches. SNOTEL estimated snowfall amounts were 14 inches at Sedgwick Peak.

Heavy Snow, Southern Hills-Albion Mountains

When: February 20, 12:00 AM MST to February 23, 4:00 PM MST
Where: Southern Hills-Albion Mountains forecast zone
Reported by: SNOTEL
Coordinates: 42.284, -113.600 (the zone’s center; the record gives no point)

Estimated SNOTEL snowfall amounts were 13 inches at Bostetter Ranger Station and 24 inches at Howell Canyon.

Winter Storm, Upper Snake River Plain

When: February 20, 12:00 AM MST to February 23, 8:00 PM MST
Where: Upper Snake River Plain forecast zone
Reported by: Department of Highways
Coordinates: 43.805, -111.767 (the zone’s center; the record gives no point)

Heavy snow and wind gusts over 40 mph caused State Highway 33 to close from Newdale to Tetonia. Recorded snow amounts were 6 inches at Sugar City and 5 inches at Saint Anthony.

Heavy Snow, Bear Lake Valley

When: February 20, 12:00 AM MST to February 23, 12:00 PM MST
Where: Bear Lake Valley forecast zone
Reported by: COOP Observer
Coordinates: 42.285, -111.330 (the zone’s center; the record gives no point)

The COOP observer in Bern measured 16 inches of snow during the extended storm.

Heavy Snow, Franklin-Eastern Oneida Region

When: February 20, 12:00 AM MST to February 23, 8:00 PM MST
Where: Franklin-Eastern Oneida Region forecast zone
Reported by: SNOTEL
Coordinates: 42.188, -112.176 (the zone’s center; the record gives no point)

The Oxford Springs SNOTEL site received an estimated 11 inches of snow.

Heavy Snow, Big Hole Mountains

When: February 20, 12:00 AM MST to February 23, 2:00 PM MST
Where: Big Hole Mountains forecast zone
Reported by: Trained Spotter
Coordinates: 43.644, -111.494 (the zone’s center; the record gives no point)

One foot of snow was recorded in Victor with 30 to 40 mph wind gusts.

Winter Storm, Arco-Mud Lake Desert

When: February 20, 12:00 AM MST to February 23, 2:00 PM MST
Where: Arco-Mud Lake Desert forecast zone
Reported by: Department of Highways
Coordinates: 43.537, -112.374 (the zone’s center; the record gives no point)

Snow and wind gusts in the 40 to 60 mph range caused blowing and drifting snow which closed US Highway 26 on the 21st from Carey to Arco. State Highway 22 was closed from Dubois to Howe. West Jefferson School District 253 was closed on the 22nd.

Winter Storm, Shoshone-Lava Beds

When: February 20, 12:00 AM MST to February 23, 12:00 PM MST
Where: Shoshone-Lava Beds forecast zone
Reported by: Department of Highways
Coordinates: 43.089, -113.918 (the zone’s center; the record gives no point)

Snow and wind gusts in the 40 to 60 mph range caused blowing and drifting snow which closed US Highway 26 on the 21st from Carey to Arco.

Winter Storm, Lost River Valleys

When: February 20, 12:00 AM MST to February 23, 12:00 PM MST
Where: Lost River Valleys forecast zone
Reported by: Department of Highways
Coordinates: 43.982, -113.727 (the zone’s center; the record gives no point)

Snow and wind gusts in the 40 to 60 mph range caused blowing and drifting snow which closed US Highway 26 on the 21st from Carey to Arco.

Winter Storm, Beaverhead-Lemhi Highlands

When: February 20, 12:00 AM MST to February 23, 12:00 PM MST
Where: Beaverhead-Lemhi Highlands forecast zone
Reported by: Department of Highways
Coordinates: 44.004, -112.761 (the zone’s center; the record gives no point)

Snow and 40 to 60 mph wind gusts closed interstate 15 from Dubois to the Montana state line on the 22nd. State Highway 22 from Dubois to Howe was also closed.

Winter Storm, Blackfoot Mountains

When: February 20, 12:00 AM MST to February 23, 12:00 PM MST
Where: Blackfoot Mountains forecast zone
Reported by: Local Official
Coordinates: 43.125, -111.858 (the zone’s center; the record gives no point)

Heavy snow with 40 to 50 mph wind gusts caused hazardous road conditions. Grace School District 148 was closed on the 22nd due to road conditions. An estimated 11 inches of snow fell at the Sheep Mountain SNOTEL site. The Bone COOP station reported 5 inches of snow and Soda Springs 7 inches.

Heavy Snow, Bear River Range

When: February 20, 12:00 AM MST to February 23, 12:00 PM MST
Where: Bear River Range forecast zone
Reported by: SNOTEL
Coordinates: 42.412, -111.568 (the zone’s center; the record gives no point)

Estimated SNOTEL amounts were 17 inches at Emigrant Summit and 32 inches at Franklin Basin.

Heavy Snow, Caribou Range

When: February 20, 12:00 AM MST to February 23, 2:00 PM MST
Where: Caribou Range forecast zone
Reported by: SNOTEL
Coordinates: 42.815, -111.502 (the zone’s center; the record gives no point)

Estimated SNOTEL amounts were 10 inches at Giveout, 17 inches at Slug Creek Divide, and 14 inches at Somsen Ranch.

Winter Weather, Southern Hills-Albion Mountains

When: February 20, 12:00 AM MST to February 23, 4:00 PM MST
Where: Southern Hills-Albion Mountains forecast zone
Reported by: SNOTEL
Coordinates: 42.284, -113.600 (the zone’s center; the record gives no point)

Estimated SNOTEL snowfall amounts were 13 inches at Bostetter Ranger Station and 24 inches at Howell Canyon. Generally lesser amounts, less than 8 inches, fell across lower elevations during this long duration winter event.

Avalanche, Bear Lake Valley

When: February 21, 2:00 PM MST to 4:00 PM MST
Where: Bear Lake Valley forecast zone
Reported by: Department of Highways
Coordinates: 42.285, -111.330 (the zone’s center; the record gives no point)

An avalanche occurred at around 2:30 PM and closed a section of US Highway 89 between Montpelier and the Wyoming border on the 21st. It completely covered a portion of the road and it was reopened by 3:30 PM.

What these are

Winter Storm: A storm that brought snow, sleet or freezing rain at warning levels, usually over several hours or days.
Heavy Snow: Snowfall reaching the local warning threshold without the other hazards of a winter storm.
Winter Weather: Snow, sleet or freezing rain below warning levels that still caused disruption, damage or casualties.
Avalanche: A mass of snow sliding down a mountainside that caused a death, an injury or damage.

After NWS Directive 10-1605, the rules offices file Storm Data by.

The same day elsewhere

Every storm in Idaho in 2023 Every state in 2023 This day in weather history Warnings in Idaho, February 2023

Sources

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: 1083680, 1083692, 1083694, 1083695, 1083696, 1083701, 1083720, 1083721, 1083724, 1083726, 1083731, 1083737, 1083738, 1083739, 1083740, 1109562, 1083697.