MissoulaAvalanche.org

Avalanche Information for West Central Montana

February 13, 2012 Avalanche Advisory

Current Danger Rating is LOW

The mountainous backcountry of west central Montana is in a period of LOW avalanche danger.

Good morning! This is Steve Karkanen with the West Central Montana Avalanche Center’s avalanche advisory for Monday February 13, 2012.

LOW avalanche danger never means NO avalanche danger as it is still possible to find isolated pockets of unstable snow on extreme terrain.

Weather and Snowpack Analysis 

The clear weather last week gave way to clouds and minor amounts of precipitation that peppered our area over the weekend.  SNOTEL sites recorded 2 to 5 inches of snow which further buried the surface hoar layer that Dudley described in our previous advisory.  While this is not much of an avalanche problem right now, this new snow easily sloughs off slopes steeper than 35 degrees particularly on more sheltered or wind loaded terrain and will be the primary concern as new snowfall accumulates or wind creates a slab on leeward terrain.

The condition where a layer of surface hoar is slowly buried a few inches at a time can catch you by surprise once enough snow accumulates to bring it to it’s breaking point.  We expect it to fail during or right after a 12 inch storm, we tend to forget about it when it takes several days to accumulate 12 inches.  It’s out there, don’t forget about it.

Weather Forecast and Avalanche Outlook

The Missoula Office of the National Weather Service is forecasting scattered mountain snow showers with only localized accumulation.  A better chance of light to moderate amounts of snow will occur Tuesday as a short wave passes through the area.  The weather is expected to remain unsettled for the period beyond Tuesday.

Expect the avalanche danger to remain similar until we begin to see significant snowfall again.  Also pay close attention to what the wind does at the ridgelines as there is plenty of snow available for transport.   Recently wind loaded terrain will be sensitive and it will be easy to generate sloughs big enough to get you in trouble if you don’t have experience with them.

Dudley issues the next advisory on Friday,  February 17.

Level 1 for Snowmobilers

There is room for more participants in this class, check out the details here.

This information is the sole responsibility of the Forest Service and does not apply to operating ski areas. The avalanche danger rating expires at midnight tonight but you can use the information we provide to help you make more informed decisions regarding travel in avalanche terrain for the next few days.

Our advisory area includes the Bitterroot Mountains from Lost Trail Pass North to Hoodoo Pass, the Rattlesnake Mountains and the Southern Swan and Mission Mountains near Seeley Lake. Avalanche information for the Lookout Pass/St. Regis Basin is available from the Idaho Panhandle Avalanche Center.