Montana, 2017

Heavy Snow in Montana, September 14 to 16, 2017

September 14 to 16, 2017 · NWS MSO · 2 events in 2 counties and zones

After a hot start to September, a cold weather system brought widespread low elevation rain and snow accumulations above 6000 feet across the Northern Rockies impacting backcountry hunters, wildfire crews and travel across mountain passes. The large degree of change coupled with the somewhat unseasonable timing of this event produced greater than normal impacts.

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.

After a hot start to September, a cold weather system brought widespread low elevation rain and snow accumulations above 6000 feet across the Northern Rockies impacting backcountry hunters, wildfire crews and travel across mountain passes. The large degree of change coupled with the somewhat unseasonable timing of this event produced greater than normal 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 Sep 14, 1:38 PM MST, 7 hours 22 minutes earlier.

Area forecast discussion, Sep 14, 1:38 PM MST, 7 hours 22 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
September 14, 9:00 PM MST to September 16, 12:00 AM MST
Where
Bitterroot / Sapphire Mountains forecast zone
Reported by
NWS Employee
Coordinates
46.508, -113.828 (the zone’s center; the record gives no point)

Up to 4 inches of snow fell across the higher terrain during this event causing snow and slush to cover parts of Skalkaho Pass and backcountry roads. Fire personnel from the Lolo Peak wildfire were cut-off from any access to the mid and upper part of the fire due to snow. Temperatures fell from the 70s and 80s in the higher terrain earlier in the week to the upper 20s to lower 30s by the 15th.

Heavy Snow, Butte / Blackfoot Region

When
September 15, 12:00 AM MST to September 16, 8:00 AM MST
Where
Butte / Blackfoot Region forecast zone
Reported by
Public
Coordinates
46.306, -113.025 (the zone’s center; the record gives no point)

Very heavy snow fell over parts of southwest Montana above 6000 feet. A person from the public located one mile east-southeast of Seven Gables Inn in Georgetown Lake measured 14 inches of total storm snowfall from this event. By the morning of the 16th Homestake Pass and MacDonald Pass were snow-covered with slick conditions.

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 2017Every state in 2017This day in weather historyWarnings in Montana, September 2017

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 2026-10-01. Each event’s entry at NCEI: 717528, 717530.