Avalanche Advisory Feb. 8, 2008

Weekend Avalanche Advisory
Posted February 8 at 0700

Good Morning! This is Dudley Improta with the West Central Montana Avalanche Center’s weekend avalanche advisory for February 8-10, 2008. The avalanche danger rating expires at midnight February 8. This report is based on field observations and data collected on Thursday and describes conditions seen at that time. This advisory is the sole responsibility of the Forest Service and does not apply to operating ski areas.
We would like to thank and acknowledge Sue and Rick Neff, local veteran skiers, for their generous donation to missoulaavalanche.org.

Weather and Snowpack Analysis

The snow in West Central Montana had started to settle but we were hit with a series of storms in the latter part of the week. It is worth noting that Idaho Department of Transportation personnel observed very deep crowns from natural avalanches along the Idaho side of Lolo Pass earlier in the week. They were there to use guns to control the snow along highway 12. It appeared these avalanches ran on the crust that formed on MLK weekend. That crust and weak snow has persisted, but it is taking some force to get it to fail in stability tests. It is buried 2 to 3 feet below the surface but still breaking cleanly. Our concern this weekend will be with the new snow from the storms that started Wednesday night.
Weather telemetry sites around the region are registering 14 to 16 inches of new snow accompanied by steady winds at 30 mph. Winds are predominately out of the West and Southwest. Observers reported up to 50cm (20 inches) of ski penetration while breaking trail. Even though observers did not report the cracking and settling of the snow like last week, they all felt the new snow with the unrelenting winds deserve attention.
You can view the snow layers on youtube:
http://www.youtube.com/watch?v=2bq62pOftjs

http://www.youtube.com/watch?v= MsJOKBpppns

Today’s Avalanche Danger

Above 5000′ in all advisory area locations, the avalanche danger is CONSIDERABLE on all slopes steeper than 30 degrees. Natural avalanches are possible and human triggered avalanches are probable. Increasing caution on steeper terrain is advised. Below 5000′ the avalanche danger is MODERATE on slopes steeper than 35 degrees and LOW at all other locations.
THE EXCEPTION TO THIS FORECAST IS THE LOOKOUT PASS AND ST. REGIS BASIN regions within the advisory area. Above 5000′ in the Lookout Pass area on all slopes steeper than 30 degrees the avalanche danger is HIGH. Natural and human triggered avalanches are likely. Travel in avalanche terrain is not recommended.

Weather Forecast and Avalanche Outlook:

A winter storm warning for West Central Montana remains in effect until 5am MST Saturday. Areas of heavy snow are predicted to continue accompanied by 25mph winds. Both Lolo Pass and Lookout Pass will be among the areas impacted. A milder westerly flow is expected to develop by Sunday with still some chances of snow. Remember most natural avalanche activity occurs during and immediately after storms and wind is a major architect of avalanches.
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If you want to send us an observation or report an avalanche, go to missoulaavalanche.org and click on “submit an observation”.

The next avalanche advisory will be posted on February 16, 2008