January 3, 2011 Avalanche Advisory
Good morning, this is Dudley Improta with the West Central Montana Avalanche Center’s avalanche advisory for January 3, 2011
Current Avalanche Danger
On all wind-loaded slopes above 6000 feet and steeper than 35 degrees there is a CONSIDERABLE avalanche hazard. On all other slopes in the advisory area above 5000 feet and steeper than 30 degrees there is a MODERATE avalanche hazard. During CONSIDERABLE hazard careful snowpack evaluation, cautious route-finding and conservative decision making are recommended.
Weather and Snowpack Analysis
We saw much improved stability in our snowpack since Thursday. Snow pits and observations from Lolo Pass, the Northern Bitterroots and the Rattlesnakes indicate a strengthening snowpack; but stability tests were showing the storm snow from Tuesday and Wednesday and a buried surface hoar layer failing with moderate to easy force.
The snow from mid-week has settled, up to 8 inches in the Rattlesnakes. This rapid settling indicates a more stable situation. Yesterday we received up to 3 to 4 inches of super-light-density snow. This snow, around 6% density, did not add much weight to the snowpack. This disturbance tracked through the Northern part of the area leaving Lolo Pass and the Rattlesnakes the beneficiary of the “arctic fluff”.
Our concern is with wind-loaded slopes on ridge tops and above tree-line. Yesterday morning high elevation winds out of the West/Northwest were recorded steady at 20mph and gusting to 30mph. Any steep open slope at higher elevations is suspect; particularly Easterly aspects. There is some very high quality riding and skiing out there; you should just be very judicious about how you approach it.
Weather Forecast and Avalanche Outlook
On Tuesday a small disturbance is expected to move into the area. Mainly light accumulations are predicted. On Wednesday a stronger disturbance should cause widespread snow; this may track through the Northern part of our advisory area.
Weather Service models are indicating a strong arctic push this weekend with sub-zero temperatures and significant snowfall.
For Tuesday and Wednesday I would expect the snowpack to continue to strengthen. There is the potential for the snow predicted for this week to fall on the weak light-density snow that fell yesterday. This could potentially form another weak layer in the snowpack.
The next advisory will be posted Friday January 7, 2011.
If you get out and see avalanche activity or want to send us quick snow observations please use our public observations form.
The Kettlehouse Brewery is sponsoring Community Unite to benefit missoulaavalanche.org on January 12, 2011. This will be at their Northside location. There will be some drawings for SCHWAG…..(sp)….stuff.
Check our Education and Events page for open Level 1 and Level 2 classes and avalanche awareness workshops.
