Montana, 2007

Heavy Snow in Montana, May 21 to 22, 2007

May 21 to 22, 2007 · NWS MSO · 2 events in 2 counties and zones

On May 21 and 22, a very strong, moist and slow moving closed low pressure system moved across Southwest Montana bringing very heavy snowfall to both the mountains and high elevated valleys. This event was a high impact event that not only caused several accidents on the highways, but caused significant tree damage as well.

Where it happened

Every event with a place to put it; 2 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

Open the live radar over this ground

The toll

Deaths
0
Injuries
0
Property damage
None recorded
Crop damage
None recorded
Events
2

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.

On May 21 and 22, a very strong, moist and slow moving closed low pressure system moved across Southwest Montana bringing very heavy snowfall to both the mountains and high elevated valleys. This event was a high impact event that not only caused several accidents on the highways, but caused significant tree damage as well.

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 May 21, 7:58 AM MST, 2 minutes earlier.

Area forecast discussion, May 21, 7:58 AM MST, 2 minutes before
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The radar

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

Open the radar archive at this moment

Event by event

2 heavy snow. Local standard time, as filed.

Heavy Snow, Bitterroot / Sapphire Mountains

When
May 21, 8:00 AM MST to May 22, 5:48 AM MST
Where
Bitterroot / Sapphire Mountains forecast zone
Reported by
Mesonet
Coordinates
46.508, -113.828 (the zone’s center; the record gives no point)

Heavy wet snow was received across the higher elevations of the Bitterroot and Sapphire Mountains. Snotel sites reported the following |total snowfall for the storm: Skalkaho Pass 13.0 inches, Black Pine 10.0 inches, Saddle Mountain 8.0 inches, and Twin Lakes 7.0 inches.

Heavy Snow, Butte / Blackfoot Region

When
May 21, 2:00 PM MST to May 22, 5:48 AM MST
Where
Butte / Blackfoot Region forecast zone
Reported by
Mesonet
Coordinates
46.306, -113.025 (the zone’s center; the record gives no point)

Widespread heavy wet snow was received across the higher valleys and mountains. Georgetown Lake received 15-22 inches, Philipsburg 16-21 inches, Avon 16-18 inches, Anaconda 7-13.5 inches, and Butte 4-6 inches of wet snow. Power outages were reported at several locations. Significant damage to trees was also reported along with several weather-realted accidents on area roads.

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 2007Every state in 2007This day in weather historyWarnings in Montana, May 2007

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: 24066, 22906.