Dec 28, 2012 @ 6:56 am

December 28, 2012 Avalanche Advisory

The avalanche danger is LOW to MODERATE throughout our advisory area.  The moderate danger rating is for wind loaded terrain steeper than 35 degrees. At all other locations and elevations the avalanche danger is low.

Good morning!  This is Steve Karkanen from the West Central Montana Avalanche Center.  This advisory would not be possible without the support of our friends group the West Central Montana Avalanche Foundation, a 501 (c) 3 non-profit whose mission is to support avalanche awareness education in western Montana.


Weather and Snowpack Analysis

Since Christmas day, area SNOTEL sites have picked up little snow but the wind continues moving snow at the highest elevations.  Thursday winds were from the southwest at a steady 15-17 mph.  Visibility was poor and the wind was moving snow onto leeward terrain. All our observers in the Bitterroot and Rattlesnake are finding mostly stable snow but all locations are showing a mid-pack density change that takes a lot of force to produce failure. The primary concern for now will be the steeper terrain that has been recently wind loaded. The layers at mid-pack may react to a big shock on wind loaded terrain or steep slope rollovers.  The northern Bitterroot has been receiving more snow than other locations but the snow structure is similar with wind loaded slopes steeper than 35 degrees being the primary concern.  It is still possible to trigger a deeper slab under these conditions so it is always important to use safe travel protocol in avalanche terrain. One at a time on steep terrain.


Weather Forecast and Avalanche Outlook

The Missoula Office of the National Weather Service is forecasting a series of minor disturbances to roll through the northern Rockies during the next few days. Very little precipitation is expected with these systems.  A warmer and dryer scenario is expected to build next week which will continue to strengthen our mountain snowpack.  It may also lead to the formation of surface hoar or near surface facets so we will be closely monitoring how things develop next week.

The avalanche danger is expected to remain similar with wind loaded terrain steeper than 35 degrees having the most potential to avalanche.

Last February, an avalanche just outside the Stevens Pass Ski Area claimed the lives of 3 people.  This happened in an area easily accessed from the ski area.  The New York Times recently published an account of the accident with details about the decision making of a large group of skiers and snowboarders who left the ski area to enjoy fresh powder in the backcountry.

Snow Fall: The Avalanche at Tunnel Creek.

This is a good reminder that when you leave the ski area boundary you are now in a backcountry setting and in many cases, in avalanche terrain.  This is certainly the case at many of the ski areas in western Montana. If you leave the ski area, you need to be prepared. That means having knowledge of avalanche terrain, the ability to make good decisions, having rescue gear like a transceiver, probe and shovel and understanding that you may be own your own for a long time if something goes sideways.  Even a minor injury or equipment failure can have life-threatening consequences.

We hope Santa left some rescue gear under the tree for you. If so, or if you want to get proficient with your transceiver, visit one of our BCA Beacon Basin transceiver training parks.

The Lolo Pass Beacon Basin is available 7 days a week and is located next to the Lolo Pass Visitor Center.  This park does not require you to check anything out, just go to the control box, read the directions and you are good to go.  We also have similar parks at the top of Montana Snowbowl and Lost Trail Ski Areas. You must have a lift ticket to access these parks.

Dudley Improta will issue the next advisory on New Years Day.  Have a safe holiday!



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 the information can help you make a more informed decision regarding travel in avalanche terrain for the next few days.

Our advisory area includes National Forest System lands in the Bitterroot Mountains from Lost Trail Pass north to Granite Pass, the Rattlesnake Mountains north of Missoula and the Southern Swan and Mission Mountains near Seeley Lake, MT. Avalanche information for the Lookout Pass/St. Regis Basin area is available from the Idaho Panhandle Avalanche Center.