Mar 7, 2011 @ 6:48 am

March 7, 2011 Avalanche Advisory

The avalanche danger is MODERATE above 5000 feet and LOW below 5000 feet.

MODERATE danger means there is heightened avalanche conditions on specific terrain features. Natural avalanches are unlikely and human-triggered avalanches are still possible. Under these conditions it is important to identify where these areas exist and travel accordingly.

LOW avalanche danger means natural and human-triggered avalanches are unlikely but you can still find unstable snow on isolated terrain features.

Hello! This is Steve Karkanen at the West Central Montana Avalanche Center with the backcountry avalanche advisory issued on Monday, March 7, 2011.

Weather and Snowpack Analysis

SNOTEL sites picked up an additional 3 to 6 inches of new snow since Friday. Temperatures have been moderate with daytime highs reaching the 30s’. The high winds that were so troublesome during the last 2-3 weeks have calmed and we’re hearing about very good skiing and riding conditions in most locations.

With just a few inches of new snow at a time, stability continues to improve and the wind-slabs we have been talking about are glued strongly and not showing signs of weakness. There is a lot of snow available to be moved around so be watching what happens the next time it gets windy at the higher elevations. There are a few pockets out there where it is still possible to trigger one of these slabs but we haven’t seen nor heard of anyone triggering anything the past few days.

I watched numerous skiers drop off Point Six into several steep, wind-loaded and rocky lines Sunday and nothing moved. It was just warm enough that sluffs were staying put but cool enough to say they were skiing powder.

It was also just about warm enough to be concerned about wet snow avalanches. Fortunately each time the sun was out long enough to warm the surface, another cloud moved in to save the day. Now that March is here we need to be watching what happens when the sun warms the snow surface. Just a few minutes of direct sun exposure is all it takes to start introducing melt-water into the upper layers of the snowpack. The immediate affect is a weakened snowpack.


Weather Forecast and Avalanche Outlook

A progressive westerly flow with multiple storm systems is expected to continue for the next several days. None of these systems is organized enough to produce heavy precipitation but we can expect a few inches of snow as each system passes. Temperatures should remain near normal for this time of year.

Expect avalanche danger conditions to remain similar until it either snows heavily or rains. The biggest concern right now is the potential for afternoon heating of the snowpack during sun breaks or the introduction of rain on all this nice snow. Snow levels should be around 4000 feet this week so rain shouldn’t be an issue yet.

I’ll issue the next advisory Friday, March 11, 2011.


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.