Heavy Snow and Winter Weather in Montana, February 5 to 8, 2021

Name: Heavy Snow and Winter Weather in Montana, February 5 to 8, 2021
Start: 2021-02-05T03:00
End: 2021-02-08T09:30
Location: Montana

February 5 to 8, 2021 · NWS TFX · 21 events in 13 counties and zones

The toll

Deaths: 0
Injuries: 0
Property damage: None recorded
Crop damage: None recorded
Events: 21

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 TFX wrote it up.

A broad, deep upper level trough set up over most of the CONUS, resulting in northwesterly flow across Montana. Multiple waves moved through the area embedded within this flow, resulting in periods of snow, which were heavy at times. In addition to the snow, winds would occasionally be gusty, and combined with low temperatures to occasionally produce low wind chills. However, wind chills warranting Wind Chill Warnings would not be seen until later in the week.

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 Great Falls, MT wrote its last area forecast discussion before the first event at Feb 4, 11:00 PM MST, 4 hours earlier.

Area forecast discussion, Feb 4, 11:00 PM MST, 4 hours before

Area Forecast Discussion National Weather Service Great Falls MT
1100 PM MST Thu Feb 4 2021

...Aviation section updated...

.UPDATE...

Moist NW flow aloft brought snow to most mountain areas this
evening, beginning a multi-day winter weather event across the
region that includes snow, for some areas continuing through Sunday,
along with the coldest temperatures of the season so far by later
this weekend. Upper level wave in NW flow moving into western BC
this evening will track into the Northern Rockies late tonight
initiating more widespread snow to develop across much of the area
by Friday morning. Onset of this first round of snow for many lower
elevation areas looks to be between 2AM and 5AM for the Great Falls,
Helena and Bozeman areas with snow continuing into late Friday
morning before decreasing across most lower elevation ares. No major
changes needed to snow amounts through Friday morning or winter
weather highlights, but did adjust timing/pops based on latest model
guidance.

A cooler airmass in Alberta filters south into north-central MT
tonight, shifting winds to the north, but the main surge of Arctic
air and much colder temperatures will arrive Friday night. Looking
ahead to tomorrow evening, will need to watch for a period of strong
north winds with with the arrival of the cold air. With snow likely
on the ground across parts of north-central MT, these winds could
lead to significant blowing/drifting snow for a period following the
frontal passage. Hoenisch

&&

.SYNOPSIS...
Periods of snow, heavy at times, will affect much of Central Montana
over the next several days. Very cold air will also move southward
into the region over the weekend. Expect the snow to decrease by
early next week, but the very cold air is likely to continue through
much of next week.

&&

.AVIATION...
1100 PM MST Thu Feb 4 2021 (05/06Z TAF period)

VFR conditions will remain widespread until about 10 or 11z Friday
morning. Until then, expect mountain snow to continue, with some
terrain obscuration continuing. Snow will begin again again from
West to East early Friday morning, which will bring lowered ceilings
and reduced visibility. This will result in MVFR to IFR conditions
for most terminals across the area by sunrise, though KHVR may
remain VFR through tomorrow afternoon. Once it begins, expect snow
to continue through the remainder of the TAF period. Ludwig

Refer to weather.gov/zlc for more detailed regional aviation weather
and hazard information.

&&

.PREV DISCUSSION...
/ISSUED 458 PM MST Thu Feb 4 2021/
Tonight through Sunday...Overall, periods of snow, heavy at times
will affect a good portion of the region from late tonight and
into Sunday. From Friday through Sunday, the main adjustment to
the forecast is to blend the NBM with colder temperatures,
adjusted POPs and QPF upward, thus we now have higher snow amounts
at lower elevations. For the Rocky Mountain Front, Central MT and
Gallatin county, the highlight has been changed to a winter storm
warning, for all elevations. The snow will begin in the mountains
tonight, and will generally move into the lower elevations on
Friday morning. Several inches of snowfall are expected each day
from Fri thru Sun, and by Sunday impacts could be high. There
continues to be the possibility that a period of heavier snowfall
could develop along the arctic boundary on Saturday afternoon into
Sunday morning as well, increasing snow totals a bit more. Wind
chill highlights might be needed by Sunday as well.

Monday through Thursday...There will be the potential for some
snow on Monday as the arctic air boundary continues to move
southward. However, as a very strong area of high pressure begins
to move southward into the region, expect drier and more stable
air to also move in, resulting in less chances for snow. Overall,
temperatures are likely to be below zero across much of the region
through much of the week. I blended the NBM with colder raw
temperatures, but again there is the potential that temperatures
could be 10 or more degrees colder across the region during this
period, especially at night, with little cloud cover.
Additionally, there might be just enough wind that wind chill
highlights might be needed. Brusda

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  20  27  -2  13 /  60  80  70  70
CTB  16  20  -6   5 /  60  80  60  70
HLN  27  37  13  27 /  60  80  70  50
BZN  22  35  13  31 /  70  80  60  60
WYS  10  26   8  24 /  80  90  30  60
DLN  20  35  17  34 /  30  50  20  30
HVR  11  15 -10   4 /  20  50  60  60
LWT  17  23  -5  12 /  80  80  80  80

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
Winter Storm Warning until 5 PM MST Sunday Broadwater...
Cascade...Central and Southern Lewis and Clark...Chouteau...
Fergus...Gallatin...Jefferson...Judith Basin...Meagher.

Winter Weather Advisory until 5 PM MST Sunday Eastern Glacier...
Eastern Pondera...Eastern Teton...Liberty...Toole.

Winter Weather Advisory until 5 PM MST Sunday Blaine...Hill.

Winter Storm Warning until 5 PM MST Sunday Northern Rocky
Mountain Front...Southern Rocky Mountain Front.

&&

http://www.weather.gov/greatfalls

Event by event

15 heavy snow, 6 winter weather. Local standard time, as filed.

Heavy Snow, Jefferson

When: February 5, 3:00 AM MST to February 7, 1:30 PM MST
Where: Jefferson forecast zone
Reported by: Social Media

Storm total snowfall of one foot reported near Clancy.

Heavy Snow, Jefferson

When: February 5, 3:00 AM MST to 10:00 PM MST
Where: Jefferson forecast zone
Reported by: Public

Public estimate of 10 inches of new snow on Friday.

Winter Weather, Cascade

When: February 5, 4:00 AM MST to February 7, 2:30 PM MST
Where: Cascade forecast zone
Reported by: Trained Spotter

One additional inch of snow fell since 2/6 at noon, resulting in a storm total of 5 inches since Friday. Overnight low was -14F.

Winter Weather, Beaverhead

When: February 5, 4:00 AM MST to February 7, 10:45 AM MST
Where: Beaverhead forecast zone
Reported by: NWS Employee

Storm total of 4.9 inches.

Winter Weather, Cascade

When: February 5, 4:00 AM MST to February 7, 10:45 AM MST
Where: Cascade forecast zone
Reported by: NWS Employee

Storm total of 4.9 inches of snow.

Heavy Snow, Judith Basin

When: February 5, 4:00 AM MST to February 7, 8:00 AM MST
Where: Judith Basin forecast zone
Reported by: Trained Spotter

Spotter estimated 12 inches storm total snow. Drifted with variable depth.

Heavy Snow, Beaverhead

When: February 5, 4:30 AM MST to February 6, 7:00 AM MST
Where: Beaverhead forecast zone
Reported by: CoCoRaHS

CoCoRaHS station mt-bv-18 reports 5.5IN of snow.

Heavy Snow, Beaverhead

When: February 5, 5:00 AM MST to February 6, 11:15 AM MST
Where: Beaverhead forecast zone
Reported by: Trained Spotter

Storm total of 6 inches of snow so far. Snow continues.

Heavy Snow, Jefferson

When: February 5, 5:00 AM MST to February 8, 7:45 AM MST
Where: Jefferson forecast zone
Reported by: Public

Public report of 12 inches of snow.

Heavy Snow, Eastern Glacier

When: February 5, 6:00 AM MST to February 6, 5:00 PM MST
Where: Eastern Glacier forecast zone
Reported by: Social Media

Estimated 7 inches of snowfall in the cut bank area since Friday.

Winter Weather, Chouteau

When: February 5, 7:00 AM MST to February 6, 7:00 AM MST
Where: Chouteau forecast zone
Reported by: COOP Observer

Co-op observer station lomm8 loma 1 wnw coop reports 3 inches of snow.

Winter Weather, Chouteau

When: February 5, 8:00 AM MST to February 6, 8:00 AM MST
Where: Chouteau forecast zone
Reported by: COOP Observer

Co-op observer station ftbm8 fort benton coop reports 3 inches of snow.

Heavy Snow, Fergus

When: February 5, 9:00 AM MST to February 6, 4:00 PM MST
Where: Fergus forecast zone
Reported by: Trained Spotter

Estimated about 7 inches storm total since Friday morning. Visibility about 1/2 mile right now.

Winter Weather, Blaine

When: February 5, 1:00 PM MST to February 6, 5:45 AM MST
Where: Blaine forecast zone
Reported by: COOP Observer

Co-op observer station cnkm8 chinook coop reports 1.5 inches of snow.

Heavy Snow, Meagher

When: February 5, 2:00 PM MST to February 6, 2:00 PM MST
Where: Meagher forecast zone
Reported by: Social Media

Estimated 10 inches of snowfall at showdown ski area in the last 24 hours. still snowing hard. report via facebook.

Heavy Snow, Fergus

When: February 5, 3:00 PM MST to February 8, 9:30 AM MST
Where: Fergus forecast zone
Reported by: Trained Spotter

Storm total snow of 9.8 inches since 3PM Friday.

Heavy Snow, North Rocky Mountain Front

When: February 5, 7:00 PM MST to February 7, 5:00 PM MST
Where: North Rocky Mountain Front forecast zone
Reported by: Social Media

Storm total snowfall of 7 inches from Friday night through Sunday mid-afternoon. Still snowing lightly, but little additional accumulation.

Heavy Snow, Southern Lewis and Clark

When: February 6, 8:00 AM MST to February 7, 8:00 AM MST
Where: Southern Lewis and Clark forecast zone
Reported by: Trained Spotter

New snow in the last 24 hours is 8 inches. Storm total snowfall of 11.9 inches.

Heavy Snow, Beaverhead

When: February 6, 12:00 PM MST to February 7, 4:00 PM MST
Where: Beaverhead forecast zone
Reported by: Trained Spotter

Storm total so far for Saturday through mid-afternoon Sunday. Still snowing.

Heavy Snow, Gallatin

When: February 6, 7:00 PM MST to February 7, 2:00 PM MST
Where: Gallatin forecast zone
Reported by: Trained Spotter

New snow accumulated 5.8 inches overnight. Snow continues.

Heavy Snow, Madison

When: February 7, 3:00 AM MST to 12:00 PM MST
Where: Madison forecast zone
Reported by: Trained Spotter

Since 3am, 10 inches of new snow (nine hours). still snowing heavy with one-eight mile visibility.

What these are

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.

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

The same day elsewhere

Every storm in Montana in 2021 Every state in 2021 This day in weather history Warnings in Montana, February 2021

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: 934983, 934984, 934825, 934828, 934974, 934985, 934812, 935019, 935026, 934982, 934979, 934978, 934980, 934822, 934998, 935028, 935010, 934993, 934820, 934981, 934997.