Montana, 2021Winter Storm in Montana, February 5 to 7, 2021
February 5 to 7, 2021 · NWS MSO · 5 events in 5 counties and zones
An Arctic cold front came over of the Continental Divide and collided with an atmospheric river of moisture from the Pacific Ocean to produce widespread wintry impacts.
Every event with a place to put it; 5 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
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- Deaths
- 1
- Injuries
- 0
- Property damage
- None recorded
- Crop damage
- None recorded
- Events
- 5
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 Arctic cold front came over of the Continental Divide and collided with an atmospheric river of moisture from the Pacific Ocean to produce widespread wintry impacts.
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 Feb 5, 3:02 PM MST, 1 hour 28 minutes earlier.
Area forecast discussion, Feb 5, 3:02 PM MST, 1 hour 28 minutes before
Area Forecast Discussion
National Weather Service Missoula MT
302 PM MST Fri Feb 5 2021
...Major Winter Storm for the N. Rockies, Followed by Potentially
Dangerous Cold and Wind Chills...
.DISCUSSION...Beginning with an overview, there is a push of
Pacific moisture streaming around a high pressure ridge in the
Eastern Pacific. We have good confidence this feed will surge
again tomorrow morning and not be cut off until Sunday. However,
moisture looks to continue in west central Montana and central
Idaho through at least Monday, which increases the snowfall
potential. The second part of the equation is a dangerously cold
high pressure system pushed through Edmonton, Canada this
afternoon on its way to camp out in Eastern Montana for a
prolonged period of time. We have good confidence this Arctic air
mass will push across the Continental Divide making it as far as
west central Montana by early Sunday morning. At least along the
Divide, our confidence has grown for extremely dangerous cold
temperatures and wind chills from Monday through Wednesday.
Specifics:
Northwest MT: This evening a weak push of Arctic will interact
with upslope light snow currently falling. This will bring a
shortlived but intense period of snow, this area of snowfall may
make it as far as Kalispell. Although gusty west winds will shift
to the northeast, winds should stay sufficiently weak to not cause
impacts. Beginning tomorrow morning, the next warm, moist
overrunning event will begin. Snowfall will gradually increase in
intensity through the afternoon. The highest snowfall amounts are
expected in the Seeley/ Swan Valleys with amounts of 12 to 18
inches. By midday, the next stronger push of Arctic air will work
its way through Bad Rock Canyon, bringing northeasterly winds
potentially gusting over 40 MPH. Expect intense snow squalls as
the Arctic air interacts with moist Pacific air. Initial
temperatures will be relatively warm and some melting of snow will
happen on roads, with rapidly dropping temperatures post frontal
a refreeze is possible. Strong winds will cause blowing and
drifting of snow, reducing visibilities and causing roads
conditions to change rapidly. Finally, from Sunday onward a
dangerously cold air mass will impact the area. By Wednesday, low
temperatures from -15 to -30 are possible, and with perfect
conditions some areas may see -40.
West Central MT: Convective snow showers this afternoon will give
way to a short respite through Saturday morning. The next surge
of Pacific moisture will begin to affect Lookout Pass by mid
morning. Expect intensities to quickly ramp up by noon. throughout
the afternoon areas along I-90 will see periods of moderate
snowfall. During the evening an Arctic air mass will make its way
south and west towards the Missoula Valley. The interaction of
this boundary with the Pacific air mass will cause a period of
intense snowfall, rapidly falling temperatures, and gusty winds
blowing and drifting snow. The interesting thing is the models
have this boundary stalling in the west central MT area for a
prolonged period. If this happens a prolonged period of moderate
to heavy snowfall can be expected. The I-90 corridor is forecast
to receive 12 to 18 inches east of Missoula, and Missoula and west
8 to 12 inches. With the gusty east winds, periods of near white
out conditions are possible. Snow will begin to wind down on
Monday. Then some of the coldest temperatures since 2014 are
possible, with the coldest morning on Wednesday.
Southwest MT: Light snow will begin during the afternoon Saturday,
as an Arctic air mass crosses the Continental Divide a period of
intense snowfall is expected. Additionally, easterly winds will
cause dangerous wind chills, and blowing and drifting of snow.
Depending on where this Arctic boundary stalls out, a prolonged
period of moderate snow may develop. Tuesday onward, a dangerously
cold air mass will entrench itself over our area. Under perfect
conditions, our coldest valleys could see temperatures as low as
-40 Wednesday morning.
Central Idaho: Beginning tomorrow morning a very moist air mass
will begin to affect the area. One to two feet is expected by
Monday in the mountains. There will be Arctic air involved in this
system, at this time we do not believe it is strong enough to make
it into central Idaho. That said, a general cooling trend will
begin saturday through Wednesday.
Lemhi County, ID: Light snow is expected to develop late on
Saturday. At this time heavy snowfall looks to be restricted to
Lost Trail Pass, and the spine of the Beaverhead Mountains. A
shift southward with a moist Pacific air mass could drastically
increase snow amounts, so please check weekend updates. After
Monday, very cold temperatures are expected to settle into the
valleys. Low temperatures will drop into the single digits below
zero to teens below.
&&
.AVIATION...Widespread snow this morning has transitioned into
convective showers, mainly restricted to higher terrain. This
evening cloud cover will increase and the next surge of Pacific
moisture will move over the area. Tomorrow, light snow will
overspread the Northern Rockies, gradually increasing in
intensity. As an Arctic air mass interacts with this moist air,
expect a period of intense snowfall. Then for KGPI strong
northeast winds will develop late day, reducing visibilities in
blowing snow. Snow is expected to taper off in northwest Montana
after the Arctic invasion. For west central Montana and central
Idaho, a period of moderate to heavy will develop Saturday
afternoon. Expect lowering ceilings and visibilities with heavier
snowfall. Overnight Saturday, the Arctic air will bring strong
easterly winds for KMSO and KBTM reducing visibilities.
&&
.MSO WATCHES/WARNINGS/ADVISORIES...
MT...Winter Storm Watch from Saturday afternoon through Monday
morning Missoula/Bitterroot Valleys.
Winter Storm Watch from Saturday morning through Monday morning
Lower Clark Fork Region.
Winter Storm Warning from 11 AM Saturday to 11 AM MST Sunday
Flathead/Mission Valleys.
Winter Storm Warning from 5 PM this afternoon to 11 AM MST
Sunday West Glacier Region.
Winter Weather Advisory from 11 AM Saturday to 11 AM MST Sunday
Kootenai/Cabinet Region.
Winter Storm Watch from Saturday afternoon through Monday
morning Bitterroot/Sapphire Mountains.
Winter Storm Warning from 11 AM Saturday to 11 AM MST Sunday
Potomac/Seeley Lake Region.
Winter Storm Watch from Saturday afternoon through Monday
morning Butte/Blackfoot Region.
ID...Winter Storm Watch from Saturday morning through Sunday
afternoon Northern Clearwater Mountains...Southern
Clearwater Mountains.
&&In the hours before
Local storm report, Feb 5, 1:57 PM MST, 2 hours 33 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE MISSOULA MT
157 PM MST FRI FEB 5 2021
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
1000 AM HEAVY SNOW CARDIFF 46.57N 115.81W
02/05/2021 M11.0 INCH CLEARWATER ID TRAINED SPOTTER
25 INCHES ON THE GROUND.
&&Local storm report, Feb 5, 2:01 PM MST, 2 hours 29 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE MISSOULA MT
201 PM MST FRI FEB 5 2021
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
1100 AM HEAVY SNOW PIERCE 46.49N 115.80W
02/05/2021 E12.0 INCH CLEARWATER ID PUBLIC
&&Local storm report, Feb 5, 2:05 PM MST, 2 hours 25 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE MISSOULA MT
205 PM MST FRI FEB 5 2021
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
1000 AM SNOW 4 NE OROFINO 46.52N 116.20W
02/05/2021 E6.0 INCH CLEARWATER ID TRAINED SPOTTER
&&Local storm report, Feb 5, 2:11 PM MST, 2 hours 19 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE MISSOULA MT
211 PM MST FRI FEB 5 2021
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0900 AM SNOW 3 ENE OROFINO 46.50N 116.20W
02/05/2021 E0.5 INCH CLEARWATER ID TRAINED SPOTTER
THEY THINK THE SNOW LEVEL MIGHT HAVE BEEN
AROUND 1800 FEET. THEY HAD A MIX OF RAIN AND
SNOW.
&&Local storm report, Feb 5, 2:20 PM MST, 2 hours 10 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE MISSOULA MT
220 PM MST FRI FEB 5 2021
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
1200 PM HEAVY SNOW 5 NNE ELK RIVER 46.84N 116.12W
02/05/2021 M14.0 INCH CLEARWATER ID PUBLIC
ELK BUTTE SNOTEL AT 5690 FT. THE SNOW AMOUNT
IS THE SNOW DEPTH INCREASE. 1.90 INCHES OF
SNOW WATER EQUIVALENT.
&&Local storm report, Feb 5, 3:08 PM MST, 1 hour 22 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE MISSOULA MT
308 PM MST FRI FEB 5 2021
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
1200 PM HEAVY SNOW 2 N ELK CITY 45.86N 115.44W
02/05/2021 M15.0 INCH IDAHO ID TRAINED SPOTTER
&&Winter Storm, West Glacier Region
- When
- February 5, 4:30 PM MST to February 7, 8:00 AM MST
- Where
- West Glacier Region forecast zone
- Deaths
- 0 direct, 1 indirect
- Reported by
- Department of Highways
- Coordinates
- 47.971, -114.069 (the zone’s center; the record gives no point)
Widespread snow, wind, and dangerously low wind chills were observed. Snow amounts generally ranged from 5-14 inches with 22 inches reported near Marias Pass. Easterly wind gusts of 30-40 miles per hour resulted in blowing and drifting snow with wind chills of -15F to -30F at lower elevations and -35F to -55F at higher elevations. Dangerous avalanche conditions developed because of the wind and snow with one avalanche related fatality reported in the Swan Range near Wildcat Lake. This winter storm also created significant challenges for plow crews along US Highway 2.
Winter Storm, Butte / Blackfoot Region
- When
- February 5, 9:05 PM MST to February 7, 10:00 AM MST
- Where
- Butte / Blackfoot Region forecast zone
- Reported by
- Department of Highways
- Coordinates
- 46.306, -113.025 (the zone’s center; the record gives no point)
Snow, wind, blowing snow, and low wind chill values were all observed. A flash freeze occurred late on the 5th into the morning hours of the 6th causing icy conditions on Interstate 90. Periods of severe driving conditions were also reported by the state highway department through the morning of the 7th. Total snowfall ranged from 10-20 inches with the highest amount of 24 inches near Avon. Wind chills of -20F to -35F were noted as well.
Winter Storm, Potomac / Seeley Lake Region
- When
- February 6, 11:00 AM MST to February 7, 8:00 AM MST
- Where
- Potomac / Seeley Lake Region forecast zone
- Reported by
- Public
- Coordinates
- 46.986, -113.597 (the zone’s center; the record gives no point)
Wind and heavy snow resulted in difficult driving conditions and natural avalanches in the backcountry. Snow totals ranged from 10-20 inches with the greatest total of 23.5 inches just east of Seeley Lake. Wind chill values of -10F to -20F were also observed.
Winter Storm, Bitterroot / Sapphire Mountains
- When
- February 6, 9:00 PM MST to February 7, 10:00 AM MST
- Where
- Bitterroot / Sapphire Mountains forecast zone
- Reported by
- Department of Highways
- Coordinates
- 46.508, -113.828 (the zone’s center; the record gives no point)
Snow bands created severe driving conditions as reported by the state highway department near Lolo Pass and Lost Trail Pass. Snow totals ranged from 9 to 21 inches with wind gusts to 25 miles per hour.
Winter Storm, Missoula / Bitterroot Valleys
- When
- February 6, 10:30 PM MST to February 7, 11:00 AM MST
- Where
- Missoula / Bitterroot Valleys forecast zone
- Reported by
- Social Media
- Coordinates
- 46.560, -114.023 (the zone’s center; the record gives no point)
Heavy snow, gusty winds, and snow bands brought difficult driving conditions. Snow amounts ranged from 2-4 inches in the Missoula Valley with 6-10 inches in the Bitterroot Valley. The southern Bitterroot Valley experienced the heaviest snow with 13-14 inches reported around Conner and Darby. Gusty winds and cold temperatures resulted in wind chills as low as -15F.
- Winter Storm
- A storm that brought snow, sleet or freezing rain at warning levels, usually over several hours or days.
After NWS Directive 10-1605, the rules offices file Storm Data by.
- Extreme Cold in North Dakota, February 5 to 15, 202136 events
- Winter Storm and Winter Weather in Nebraska, February 5 to 7, 202129 events
- Heavy Snow and Winter Weather in Montana, February 5 to 8, 202121 events
- Cold in Montana, February 5 to 15, 202114 events
- Winter Storm in Nebraska, February 5 to 6, 20216 events
- Winter Weather in Michigan, February 5 to 8, 20214 events
- Heavy Snow and High Wind in Colorado, February 5 to 7, 202171 kt wind · 4 events
- High Wind in Nevada, February 5, 202158 kt wind · 3 events
- Winter Weather in Maryland, February 5, 20212 events
- High Wind in Texas, February 5, 202161 kt wind · 2 events
- Marine High Wind in Lake Erie, February 5, 202150 kt wind · 1 event
- Dense Fog in California, February 5, 20211 event
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: 937870, 937882, 937880, 937877, 937875.