Montana, 2021Heavy Snow in Montana, January 2 to 3, 2021
January 2 to 3, 2021 · NWS MSO · 1 event in 1 county or zone
An atmospheric river, or very moist plume of Pacific moisture, brought heavy mountain snowfall above 4,500 feet across the Idaho Panhandle into northwest Montana.
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.
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- Deaths
- 0
- Injuries
- 0
- Property damage
- None recorded
- Crop damage
- None recorded
- Events
- 1
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.
An atmospheric river, or very moist plume of Pacific moisture, brought heavy mountain snowfall above 4,500 feet across the Idaho Panhandle into northwest Montana.
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 Missoula, MT wrote its last area forecast discussion before the first event at Jan 2, 1:59 PM MST, 3 hours 31 minutes earlier.
Area forecast discussion, Jan 2, 1:59 PM MST, 3 hours 31 minutes before
Area Forecast Discussion
National Weather Service Missoula MT
159 PM MST Sat Jan 2 2021
.DISCUSSION...Mixed valley precipitation, mountain snow, and
gusty winds remain the main focus for tonight and Sunday’s
weather system. Well above normal atmospheric moisture is moving
into the Pacific Northwest with the arrival of a warm front, that
will reach the Northern Rockies this evening. Strong winds are
likely to develop in the high terrain overnight with southerly
wind prone lower elevation spots such as Grangeville. Most of the
valleys in central Idaho and western Montana will have down-
sloping affects which will limit showers, but the high terrain,
including Lookout Pass will have periods of heavy snow overnight
and during Sunday morning. One inch per hour snow rates are
expected in the high terrain and a winter storm warning remains in
effect for Lookout Pass. Rising snow levels will keep most
valleys in mixed precipitation or rain, but snow levels are less
certain in northwest Montana so those near the ID/MT border may
have more snow than is currently reflected in the forecast.
A cold front is currently forecast to pass through the region
during Sunday morning, which will cause gusty winds and lowering
snow levels. Wind gusts over 40 mph look to be common with the
cold front passage but gusts over 50 mph are also possible.
Western Montana appears to receive the brunt of the wind, the
strongest winds are expected along the Highway 200, Highway 12
and I-90 corridors east of Missoula. Multiple wind highlights have
been issued.
Moisture profiles show quickly drying conditions behind the front
so showers are expected to decrease in coverage by late morning.
Additional fronts are lined up in the Pacific and forecast to
bring showers. The next weather system is expected Monday through
Tuesday morning, initially with higher snow levels, and another is
possible Wednesday through Thursday morning. These system will
bring accumulating snow to the higher terrain, while the valleys
will be experience a wintry mix. Each disturbance appears to cause
gusty westerly winds to the Northern Rockies.
&&
.AVIATION...Water vapor loops show a warm front moving into the
region that is expected to spread cloud cover and heavy mountain
snow to central Idaho and western Montana. Strong winds are likely
with the incoming weather system, first in the the mountains
followed by widespread valley winds Sunday morning. Terrain
winds overnight and Sunday morning could gust over 50 knots which
will cause wind shear concerns at all TAF sites. Gusty winds will
then associate with the cold front mainly between 03/1500z and
03/1800z.
&&
.MSO WATCHES/WARNINGS/ADVISORIES...
MT...Wind Advisory from 8 AM to 5 PM MST Sunday Missoula/Bitterroot
Valleys.
Winter Storm Warning from 5 PM this afternoon to 1 PM MST Sunday
Lower Clark Fork Region.
Wind Advisory from 2 AM to 5 PM MST Sunday Flathead/Mission
Valleys...Kootenai/Cabinet Region.
Winter Weather Advisory from 11 PM this evening to 1 PM MST
Sunday West Glacier Region.
Winter Weather Advisory from 5 PM this afternoon to 1 PM MST
Sunday Bitterroot/Sapphire Mountains.
Wind Advisory from 8 AM to 5 PM MST Sunday Potomac/Seeley Lake
Region.
Wind Advisory from 8 AM to 5 PM MST Sunday Butte/Blackfoot
Region.
ID...Winter Weather Advisory from 4 PM this afternoon to noon PST
Sunday ABOVE 3500 FEET for the Northern Clearwater
Mountains...Southern Clearwater Mountains.
&&Heavy Snow, Lower Clark Fork Region
- When
- January 2, 5:30 PM MST to January 3, 10:30 AM MST
- Where
- Lower Clark Fork Region forecast zone
- Reported by
- Department of Highways
- Coordinates
- 47.286, -114.685 (the zone’s center; the record gives no point)
Heavy snow developed at Lookout Pass by late evening, and continued through daybreak on the 3rd. The Montana Department of Transportation labeled the stretch of Interstate 90 from Lookout to Taft as severe driving conditions from 7 am to around 10 am MST. The Lookout SNOTEL reported 1.50 inches of snow water equivalent during this event, which equates to 12 to 14 inches of snowfall at the pass.
- Heavy Snow
- Snowfall reaching the local warning threshold without the other hazards of a winter storm.
After NWS Directive 10-1605, the rules offices file Storm Data by.
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- High Wind in Wyoming, January 2 to 4, 202171 kt wind · 9 events
- Winter Storm in Maine, January 2, 20216 events
- High Wind in Oregon, January 2 to 3, 202172 kt wind · 4 events
- Heavy Rain in Georgia, January 2, 20213 events
- Dense Fog in Colorado, January 2, 20213 events
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- High Wind in Montana, January 2 to 3, 202152 kt wind · 3 events
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: 935958.