Montana, 2011

Heavy Snow in Montana, December 20 to 21, 2011

December 20 to 21, 2011 · NWS MSO · 4 events in 2 counties and zones

A Pacific storm moved across western Montana and brought widespread snowfall. Reported storm totals were from 2 inches to 5 inches.

Where it happened

Every event with a place to put it; 4 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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The toll

Deaths
0
Injuries
0
Property damage
None recorded
Crop damage
None recorded
Events
4

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 MSO wrote it up.

A Pacific storm moved across western Montana and brought widespread snowfall. Reported storm totals were from 2 inches to 5 inches.

The radar

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

Open the radar archive at this moment

Event by event

4 heavy snow. Local standard time, as filed.

Heavy Snow, Flathead/Mission Valleys

When
December 20, 11:00 PM MST to December 21, 7:16 AM MST
Where
Flathead/Mission Valleys forecast zone
Reported by
Trained Spotter
Coordinates
47.872, -114.424 (the zone’s center; the record gives no point)

A spotter measured 5.2 inches of snow 4 miles northeast of Ronan.

Heavy Snow, Missoula / Bitterroot Valleys

When
December 21, 1:00 AM MST to 7:16 AM MST
Where
Missoula / Bitterroot Valleys forecast zone
Reported by
Trained Spotter
Coordinates
46.560, -114.023 (the zone’s center; the record gives no point)

A spotter measured 3.5 inches of snow in Evaro.

Heavy Snow, Flathead/Mission Valleys

When
December 21, 1:00 AM MST to 7:16 AM MST
Where
Flathead/Mission Valleys forecast zone
Reported by
Trained Spotter
Coordinates
47.872, -114.424 (the zone’s center; the record gives no point)

A spotter measured 3.3 inches of snow 3 miles north-northeast of Bigfork.

Heavy Snow, Flathead/Mission Valleys

When
December 21, 1:00 AM MST to 7:45 AM MST
Where
Flathead/Mission Valleys forecast zone
Reported by
Public
Coordinates
47.872, -114.424 (the zone’s center; the record gives no point)

The public measured 4.5 inches of snow 12 miles northeast of Polson.

What these are

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.

The same day elsewhere

More

Every storm in Montana in 2011Every state in 2011This day in weather historyWarnings in Montana, December 2011

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 2026-09-30. Each event’s entry at NCEI: 356340, 356341, 356342, 356352.