Blizzard and Avalanche in Montana, February 21 to 23, 2021

Name: Blizzard and Avalanche in Montana, February 21 to 23, 2021
Start: 2021-02-21T07:15
End: 2021-02-23T03:54
Location: Montana

February 21 to 23, 2021 · NWS TFX · 35 events in 17 counties and zones

The toll

Deaths: 0
Injuries: 0
Property damage: None recorded
Crop damage: None recorded
Events: 35

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.

Winds began to increase over North-Central and Southwestern Montana early on Sunday February 21 as a strong upper level jet roared overhead. Winds were generally strongest and most persistent across the plains during the day on Sunday, thanks to a strong pressure gradient that developed along the Rocky Mountain Front. After seeing widespread wind gusts over 60 mph, with isolated gusts in excess of 80 mph, during the day on Sunday, winds would generally begin to decrease late Sunday and early Monday closer to the Rocky Mountain Front, though winds around the Lewistown and Fort Belknap areas peaked early Monday morning, when some wind damage occurred in these areas. Winds area-wide would be a bit lighter during the day on Monday, but a final push of higher winds occurred late Monday night as a cold front pushed through the area.

In addition to causing some damage across the plains, the strong winds also combined with a fairly fresh snowpack, which resulted in areas of intense blowing snow, which caused blizzard conditions along the Rocky Mountain Front. Areas of blowing snow also occurred in the Lewistown area, which would result in the closure of highway 191 between Harlowton and Judith Gap, but not before numerous traffic incidents had occurred.

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 21, 4:20 AM MST, 2 hours 55 minutes earlier.

Area forecast discussion, Feb 21, 4:20 AM MST, 2 hours 55 minutes before

Area Forecast Discussion
National Weather Service Great Falls MT
420 AM MST Sun Feb 21 2021

Updates Aviation Section.

.SYNOPSIS...
Increasing winds today along with snow along the Divide will
cause slippery road conditions and reduced visibilities at times.
Periods of strong winds are expected at times on this morning
through Monday night over North Central and Central MT.
Temperatures warm to about 10 degrees above normal by Monday, but
cool off on Tuesday, as a front crosses the region and brings some
snow with it.

&&

.DISCUSSION...
This morning through Tuesday...Snow Showers and strong winds begin
to develop this morning along the Northern Rocky Mountain Front and
spread from west to east over North Central MT throughout the day
today. A blizzard warning has been issued for areas above 5000 ft
over the the Northern Rocky Mountain Front, given the wind gusts
exceeding 70 mph along with a fair amount of snow. The high wind
warning remains unchanged in area and time for now. It still looks
like the high winds should diminish below warning criteria this
evening as we lose the daytime mixing, but we will need to watch for
the potential need for extending the warning later depending on how
strong the front this evening/night ends up being. Blowing snow will
start to become less of an impact over the next few days over the
Plains as the snow compacts/melts and becomes harder to blow around
with the warmer temperatures. Afternoon temperatures will continue
the warming trend for through Tuesday, with widespread 40s at lower
elevations and perhaps even a few places reaching 50 degrees on
Monday. Lighter snow is expected for much of the plains along or
behind the front, but amounts and impacts look on the low side for
now. Expect colder air and light snow to move back into the region,
with Tuesday highs currently forecast to be 10 to 15 degrees cooler
than today.

Tuesday night through Saturday... Below normal temperatures are
expected from Wednesday through next Saturday, but extreme cold is
not anticipated. We can expect periods of light snow over the
Rocky Mountain Front and mostly Southwest MT, with the best chance
currently appearing to be Thursday afternoon through Friday
night. Overall snow accumulations look light at this time, but
we'll have to see how the expected timing and snowfall rates
evolve as to whether any advisories may be needed.

&&

.AVIATION...
420 AM MST Sat Feb 21 2021 (21/12Z TAF period)

Scattered snow and strong gusty winds begin to pick up this morning
along the Rocky Mountain Front, With lowering VFR conditions
becoming MVFR to IFR during any passing showers. LLWS will
increasingly become an issue over north-central and southwest MT
this morning, with strong winds over KCTB this morning, and
spreading east across north-central throughout the day.

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

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  41  36  48  27 /   0   0   0  30
CTB  39  34  44  23 /   0  10  10  50
HLN  43  35  50  29 /  10  10  10  60
BZN  38  27  46  25 /  10  10  10  70
WYS  25  14  32  15 /  30  30  30  80
DLN  34  23  43  20 /  10  10  10  60
HVR  41  32  47  25 /   0   0  10  40
LWT  38  31  45  25 /   0   0   0  30

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
High Wind Warning from 6 AM this morning to 10 PM MST Monday
Cascade...Central and Southern Lewis and Clark...Chouteau...
Eastern Pondera...Eastern Teton...Judith Basin...Liberty...Toole.

High Wind Warning from 3 PM this afternoon to 10 PM MST Monday
Blaine...Fergus...Hill...Meagher.

Winter Weather Advisory from 5 AM early this morning to 3 PM MST
this afternoon above 5000 feet for Northern Rocky Mountain Front.

Blizzard Warning from 3 PM this afternoon to 11 AM MST Tuesday
above 5000 feet for Northern Rocky Mountain Front.

High Wind Warning until 10 PM MST Monday Eastern Glacier...
Northern Rocky Mountain Front...Southern Rocky Mountain Front.

&&

http://www.weather.gov/greatfalls

In the hours before

Local storm report, Feb 21, 4:41 AM MST, 2 hours 34 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREAT FALLS MT
441 AM MST SUN FEB 21 2021

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0305 AM     HIGH SUST WINDS  3 SW CUT BANK           48.60N 112.37W
02/21/2021  M42 MPH          GLACIER            MT   ASOS

            SUSTAINED WINDS AVERAGED 42 MPH FROM 205 AM
            TO 305 AM. PEAK WIND GUST WAS 54 MPH AT 247
            AM. ASOS STATION KCTB CUT BANK AIRPORT.

&&

BRUSDA

Local storm report, Feb 21, 4:49 AM MST, 2 hours 26 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREAT FALLS MT
449 AM MST SUN FEB 21 2021

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0410 AM     HIGH SUST WINDS  2 NW PENDROY            48.07N 112.33W
02/21/2021  M42 MPH          TETON              MT   MESONET

            SUSTAINED WIND AVERAGED 42 MPH BETWEEN 310
            AM AND 410 AM. PEAK WIND GUST WAS 53 MPH AT
            335 AM DURING THIS PERIOD. MESONET STATION
            MTPND PENDROY (MT DOT).

&&

BRUSDA

Local storm report, Feb 21, 5:15 AM MST, 2 hours before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREAT FALLS MT
515 AM MST SUN FEB 21 2021

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0414 AM     NON-TSTM WND GST 3 SW CUT BANK           48.60N 112.37W
02/21/2021  M61 MPH          GLACIER            MT   ASOS

            ASOS STATION KCTB CUT BANK AIRPORT.

&&

BRUSDA

Local storm report, Feb 21, 5:19 AM MST, 1 hour 56 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREAT FALLS MT
519 AM MST SUN FEB 21 2021

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0439 AM     NON-TSTM WND GST 2 SE BROWNING           48.54N 112.98W
02/21/2021  M68 MPH          GLACIER            MT   MESONET

            MESONET STATION MTBWG BROWNING (MT DOT).

&&

BRUSDA

Local storm report, Feb 21, 5:20 AM MST, 1 hour 55 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREAT FALLS MT
520 AM MST SUN FEB 21 2021

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0455 AM     HIGH SUST WINDS  2 SE BROWNING           48.54N 112.98W
02/21/2021  M47 MPH          GLACIER            MT   MESONET

            SUSTAINED WINDS AVERAGED 47 MPH BETWEEN 355
            AM AND 455 AM. PEAK GUST WAS 68 MPH AT 439
            AM DURING THIS PERIOD. MESONET STATION MTBWG
            BROWNING (MT DOT).

&&

BRUSDA

Local storm report, Feb 21, 5:21 AM MST, 1 hour 54 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREAT FALLS MT
521 AM MST SUN FEB 21 2021

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0431 AM     NON-TSTM WND GST 1 ENE EAST GLACIER PARK 48.45N 113.20W
02/21/2021  M62 MPH          GLACIER            MT   MESONET

            MESONET STATION MTBRN TWO MEDICINE BRIDGE
            (MT DOT).

&&

BRUSDA

Event by event

33 high wind, 1 blizzard, 1 avalanche. Local standard time, as filed.

High Wind, Eastern Pondera

When: February 21, 7:15 AM MST
Where: Eastern Pondera forecast zone
Measured: 55 kt (63 mph) measured gust
Reported by: Mesonet

Mesonet station mtm73, ledger n mda reports wind gust of 63 MPH.

High Wind, Cascade

When: February 21, 11:30 AM MST
Where: Cascade forecast zone
Measured: 56 kt (64 mph) measured gust
Reported by: Mesonet

Mesonet station mtm76, cascade e mda.

Blizzard, North Rocky Mountain Front

When: February 21, 12:30 PM MST to 3:30 PM MST
Where: North Rocky Mountain Front forecast zone
Reported by: Department of Highways

Montana DOT webcams showed very poor visibility, with local weather stations showing winds in excess of 35 mph near East Glacier. Conditions were likely much worse at higher elevations, such as Marias Pass, but there is no webcamera to confirm. Attached is a Twitter thread showing the conditions at East Glacier.

High Wind, Eastern Pondera

When: February 21, 1:30 PM MST
Where: Eastern Pondera forecast zone
Measured: 51 kt (59 mph) measured gust
Reported by: Mesonet

Francis heights rd mesonet reports wind gust of 59 MPH.

High Wind, Southern Rocky Mountain Front

When: February 21, 2:45 PM MST
Where: Southern Rocky Mountain Front forecast zone
Measured: 74 kt (85 mph) measured gust
Reported by: Mesonet

Mesonet station delmt dellwo (mcscn) reports wind gust of 85 MPH.

High Wind, Southern Rocky Mountain Front

When: February 21, 2:54 PM MST
Where: Southern Rocky Mountain Front forecast zone
Measured: 57 kt (66 mph) measured gust
Reported by: Mesonet

Elk Creek mesonet reports wind gust of 66 MPH.

High Wind, Gallatin

When: February 21, 2:57 PM MST
Where: Gallatin forecast zone
Measured: 52 kt (60 mph) measured gust
Reported by: Mesonet

Mesonet station mtbzh bozeman pass (mt dot).

High Wind, North Rocky Mountain Front

When: February 21, 3:09 PM MST
Where: North Rocky Mountain Front forecast zone
Measured: 63 kt (72 mph) measured gust
Reported by: Mesonet

Mesonet station mtbwg browning (mt dot) reports 73 MPH wind gust.

High Wind, Eastern Glacier

When: February 21, 4:24 PM MST
Where: Eastern Glacier forecast zone
Measured: 70 kt (81 mph) measured gust
Reported by: ASOS

Asos station kctb cut bank airport reports 81 MPH wind gust.

High Wind, Blaine

When: February 21, 5:00 PM MST
Where: Blaine forecast zone
Measured: 60 kt (69 mph) measured gust
Reported by: Trained Spotter

Trained spotter reports wind gust of 69 MPH. Snow is crusted over and not blowing around.

High Wind, Toole

When: February 21, 5:21 PM MST
Where: Toole forecast zone
Measured: 61 kt (70 mph) measured gust
Reported by: Mesonet

Mesonet station mtswt sweetgrass (mt dot) records wind gust of 70 MPH.

High Wind, Toole

When: February 21, 8:05 PM MST
Where: Toole forecast zone
Measured: 52 kt (60 mph) measured gust
Reported by: Mesonet

Mesonet station dw9605 galata reports wind gust of 60 MPH.

High Wind, Liberty

When: February 21, 8:15 PM MST
Where: Liberty forecast zone
Measured: 55 kt (63 mph) measured gust
Reported by: Public

Public davis vantage weather station reports wind gust of 63 MPH.

High Wind, Hill

When: February 21, 8:55 PM MST
Where: Hill forecast zone
Measured: 56 kt (64 mph) measured gust
Reported by: Mesonet

Mesonet station mtinv inverness (mt dot) reports wind gust of 65 MPH.

High Wind, Fergus

When: February 21, 9:59 PM MST
Where: Fergus forecast zone
Measured: 61 kt (70 mph) measured gust
Reported by: AWOS

Awos station k1om oscar.

High Wind, Blaine

When: February 21, 10:18 PM MST
Where: Blaine forecast zone
Measured: 50 kt (58 mph) measured gust
Reported by: Mesonet

Wind gust of 58 MPH measured at Fort Belknap Raws. Later, a gas station pump covering was damaged (blown off) and power outages occurred through night.

High Wind, Chouteau

When: February 21, 10:23 PM MST
Where: Chouteau forecast zone
Measured: 67 kt (77 mph) measured gust
Reported by: Mesonet

Mesonet station mtlom loma (mt dot).

High Wind, Fergus

When: February 21, 10:56 PM MST
Where: Fergus forecast zone
Measured: 67 kt (77 mph) measured gust
Reported by: AWOS

Delta AWOS reports 77 mph wind gust.

High Wind, Meagher

When: February 21, 11:09 PM MST
Where: Meagher forecast zone
Measured: 61 kt (70 mph) measured gust
Reported by: Mesonet

Lennep mesonet reports wind gust of 70 MPH.

High Wind, Southern Rocky Mountain Front

When: February 21, 11:58 PM MST
Where: Southern Rocky Mountain Front forecast zone
Measured: 52 kt (60 mph) measured gust
Reported by: AWOS

Awos station k1gm golf.

High Wind, Cascade

When: February 22, 12:44 AM MST
Where: Cascade forecast zone
Measured: 64 kt (74 mph) measured gust
Reported by: Mesonet

Mckinney mesonet reports wind gust of 74 mph.

High Wind, Gallatin

When: February 22, 12:54 AM MST
Where: Gallatin forecast zone
Measured: 55 kt (63 mph) measured gust
Reported by: Mesonet

Sourdough mesonet reports 63 mph wind gust.

High Wind, Meagher

When: February 22, 1:34 AM MST
Where: Meagher forecast zone
Measured: 59 kt (68 mph) measured gust
Reported by: Mesonet

Ef smith mesonet records wind gust of 68 MPH.

High Wind, North Rocky Mountain Front

When: February 22, 1:46 AM MST
Where: North Rocky Mountain Front forecast zone
Measured: 76 kt (87 mph) measured gust
Reported by: Department of Highways

DOT sensor just east of East Glacier Park reports 87 mph wind gust.

High Wind, Judith Basin

When: February 22, 1:58 AM MST
Where: Judith Basin forecast zone
Measured: 60 kt (69 mph) measured gust
Reported by: AWOS

Awos station k1bm bravo reports 69 MPH wind gust.

Avalanche, Southern Lewis and Clark

When: February 22, 3:44 AM MST
Where: Southern Lewis and Clark forecast zone
Reported by: Mesonet

Goss mesonet reports wind gust of 63 MPH.

High Wind, Eastern Glacier

When: February 22, 3:56 AM MST
Where: Eastern Glacier forecast zone
Measured: 63 kt (72 mph) measured gust
Reported by: ASOS

Asos station kctb cut bank airport reports wind gust of 72 mph.

High Wind, Hill

When: February 22, 4:00 AM MST
Where: Hill forecast zone
Measured: 69 kt (79 mph) measured gust
Reported by: Mesonet

Mesonet station ew1937 goldstone reports 79 mph wind gust.

High Wind, Eastern Teton

When: February 22, 4:15 AM MST
Where: Eastern Teton forecast zone
Measured: 50 kt (58 mph) measured gust
Reported by: Mesonet

Ostberg mesonet records wind gust of 58 MPH.

High Wind, Liberty

When: February 22, 4:35 AM MST
Where: Liberty forecast zone
Measured: 58 kt (67 mph) measured gust
Reported by: Mesonet

Jones mesonet reports wind gust of 67 MPH.

High Wind, Chouteau

When: February 22, 4:55 AM MST
Where: Chouteau forecast zone
Measured: 56 kt (64 mph) measured gust
Reported by: Mesonet

Rosenberg farm.

High Wind, Judith Basin

When: February 22, 5:58 AM MST
Where: Judith Basin forecast zone
Measured: 59 kt (68 mph) measured gust
Reported by: AWOS

Awos station k1cm, Charlie reports wind gust of 68 MPH. In addition, a log cabin nearby, which was on top of a knoll, was destroyed during the morning hours of Monday, February 22nd. Peak wind gusts within the region occurred between 4 and 6 am and ranged from 68 to 69 mph. Structural integrity of the building is unknown, as are the exact cost of the damages.

High Wind, Blaine

When: February 22, 8:18 AM MST
Where: Blaine forecast zone
Measured: 64 kt (74 mph) measured gust
Reported by: Mesonet

Mesonet station fblm8 fort belknap raws.

High Wind, Broadwater

When: February 23, 2:03 AM MST
Where: Broadwater forecast zone
Measured: 51 kt (59 mph) measured gust
Reported by: Mesonet

Mesonet station ginm8 ginger raws reports wind gust of 59 MPH.

High Wind, Broadwater

When: February 23, 3:54 AM MST
Where: Broadwater forecast zone
Measured: 51 kt (59 mph) measured gust
Reported by: Mesonet

Mesonet station ekhm8 elkhorn raws - 8 w townsend reports wind gust of 64 MPH.

What these are

High Wind: Sustained non-thunderstorm winds of 40 mph or more for an hour, or gusts of 58 mph or more.
Blizzard: Sustained winds or frequent gusts of 35 mph or more with falling or blowing snow that cuts visibility below a quarter mile for three hours or longer.
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 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: 935431, 935335, 935396, 935434, 935436, 935408, 935343, 935346, 935345, 935332, 935445, 935446, 935420, 935349, 935340, 935333, 935336, 935339, 935425, 935415, 935334, 935341, 935428, 935344, 935350, 935414, 935347, 935348, 935442, 935419, 935338, 935351, 935331, 935449, 935448.