Avalanche Advisory for January 12, 2009

posted: 06:30 January 12, 2009

Good morning. This is Dudley Improta with the West Central Montana Avalanche Center’s avalanche advisory for January 12, 2009. 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.
The advisory area includes the Bitterroot Mountains from Lost Trail to Lookout Pass, the Rattlesnake Mountains and the Southern Swan and Mission Mountains near Seeley Lake.

Weather and Snowpack Analysis
Temperatures have moderated and we received modest amounts of snow since Friday morning. The surface instability I described Friday morning has settled out. Snow stability testing showed an improved snowpack. Snotel sites around the region are showing seasonably warm temperatures along with 1-3” of snow accumulation for the last 48 hours. This information does not indicate great powder riding or skiing, but it does indicate a welcome stability in the snowpack. On our tour into the Rattlesnakes yesterday we observed an interesting thin crust on the snow, probably due to rime, warm temperatures and high humidity. This crust is very thin, quite skiable, and should break down; but something to keep an eye on. We have seen indications and received reports that several avalanches have run to the ground on the early December crust; most of these observations have been on NW,N,NE slopes at 6000 to 7500′. Maybe everything that was going to run on the early weakness has run; but you should pay attention on steep slopes above 6000′. The weak snow is still present at the ground level but is not responding to stability tests. Ride or ski one at a time and carry the proper equipment.

Current Avalanche Danger
The avalanche danger is MODERATE above 6000′ on all aspects and slopes steeper than 30°. The avalanche danger is LOW at all other locations.

Weather Forecast and Avalanche Outlook
It looks like weak high pressure will move into West Central Montana. There may be some scattered mountain showers in the mountains though Tuesday. Although these conditions favor a generally stable snowpack, there could be some pockets of snow instability. Since we have observed and seen reports of many natural avalanches you should consider the possibility that there may still be isolated slabs in steep terrain, particularly around rock outcrops or bands of rock on a slope. These types of terrain features tend to hold the weak snow at the bottom for a longer period of time.

If you have snow observations or any snow information you’d like to share please contact us at [email protected].

The next avalanche advisory will be posted Friday January 16th, 2009.

For specific Lookout Pass / St. Regis Basin avalanche information visit the Idaho Panhandle National Forest Avalanche .

Education and Announcements
A Beacon Basin was installed and is operable at Lolo Pass. The Beacon Basin was installed through cooperative efforts of the West Central Montana Avalanche Foundation and the U.S. Forest Service. The training opportunity will be available when the Lolo Pass Visitors Center is open. Snowmobilers will have to walk from the parking lot to use the site. You must have a transceiver to use the site. Organized groups will need a special use permit through the Forest Service if they wish to use the site for a program.

I am presenting an avalanche awareness class for the Missoula Snowgoers Snowmobile Club at 7pm in the Montana FWP Building on Tuesday January 13 at 7pm.