Dec 7, 2007 @ 12:00 am

Early Season Update

Good morning, this is Dudley Improta with the West Central Montana Avalanche Center and an early season avalanche information update for Dec. 7, 2007. Regular weekend avalanche advisories will begin on Dec. 14.

West Central Montana received some significant snow earlier this week. The Idaho / Montana border picked up more than two feet of snow by Monday evening, Dec. 3. Colder temperatures prior to that week helped form faceted snow at the ground. So we have some heavier dense snow sitting on top of that faceted snow.

We have had several reports this week of the snowpack collapsing and some natural avalanche activity on steep slopes (40 degrees). While most of the activity reported happened earlier in the week you should pay attention if plan to recreate in the high country. Some of the faceted snow on the ground may persist for some time.

If you hear collapsing noises or observe old avalanches or cracks in the snow it may behoove you to avoid steep slopes for the time being. Open north, east or northeast slopes and bowls would be most prone to any slab avalanche activity.

The Missoula office of the National Weather Service expects a cold airmass to push into West Central Montana this weekend. It is not expected to produce much snow but it is expected to cause gusty winds near ridgetops and a downward trend in temperatures. Enough wind could move snow to leeward slopes and increase the load. Colder temperatures can delay any settling or strengthening of the snowpack.

It’s still early in the season so pay attention to rocks, downfall and debris as well as the avalanche potential.

Local ski areas are opening, some of them on a limited basis. This update does not apply to operating ski areas. If you climb at an unopened ski area you should ask first and treat it as if it were the backcountry.

If you are out and see avalanche activity or just want to report some information about your observations, please send us a note from our website. We have scheduled several avalanche awareness sessions this winter and are available to give avalanche safety presentations to groups or businesses in Western Montana. Many of these sessions are posted on our Education and Events page. We are also scheduling avalanche awareness classes for grades 5-12. Call us at 406-329-3752 for further information.


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.