Current NW Montana Avalanche Advisory

This message does not apply to developed ski areas.

This is Stan Bones with a special backcountry avalanche warning issued by the U.S. Forest Service 
at 10:30 PM, Friday, January 7, 2011, for the Glacier Park and Flathead and Kootenai National Forest 
areas.

HAZARD ANALYSIS

Because of warming temperatures and heavy precipitation falling as rain or wet heavy snow we are 
currently rating the avalanche danger as HIGH between the elevations of 5,000 and 7,500 ft in the 
Mission, North Swan, and Whitefish Mountain Ranges.

Over the last 72 hours a moist flow of warm Pacific air has been pushing into NW Montana from the 
Gulf of Alaska.  All of the remotely reporting mountain weather stations across the region at 
6,000 to 6,300 ft elevation have registered temperatures hovering at or slightly above freezing 
for the last 36 hours. 

All of our mountain and valley locations have experienced some new precipitation.  The moist flow 
has been enhanced however in the Mission, North Swan, and Whitefish Mtn Ranges.  The Jewel Basin 
area, NE of Bigfork in the North Swan Range, received nearly 2 inches of snow water equivalent in 
just 18 hrs. on Friday.  This gives a total of 3 inches of snow water equivalent received in 
42 hours.  The area around the North Fork of the Jocko at the S’ern end of the Mission Range and 
the Stahl Peak area near the Canadian Border in the Whitefish Range received at least 2/3 of that 
amount.  This new precipitation was falling in the form of rain, even at 6,000 ft. elevation, and 
rain/snow mix and heavy snow above that.

Heavy precipitation, often in the form of rain, and significantly warm temperatures are currently 
producing very dangerous avalanche conditions.  The avalanche danger is rated HIGH in the Mission, 
North Swan, and Whitefish Mtn Ranges.  Travel in avalanche terrain is not recommended.  Both natural 
and human triggered avalanches are likely.  Particularly hazardous are steep gullies and large, 
steep, unanchored slopes on all aspects between the elevations of 5,000 to 7,500 feet. 

The weather forecast is for a cold air mass to push west of the Continental Divide beginning 
Saturday night.  But moisture aloft is expected to maintain mountain snowfall through Sunday.  
Until freezing temperatures and drying conditions are solidly reestablished the avalanche danger 
will remain elevated.  Backcountry travelers need to remain alert. 

The next regularly scheduled update of this avalanche advisory message will be 
Tuesday, January 11, 2011.