CBAC Early Season Advisory issued 11/22/14

Mark your calendars!  We will begin daily advisories November 24th. CBAC Annual Avalanche Awareness Night is December 6th.  The CBAC Beacon Brush up is December 7th at the Town Park.  Look for more information to follow.

Highlights

Another large winter storm is at our doorstep and will be responsible for rapidly increasing avalanche danger Saturday night into Sunday. Human triggered avalanches will be likely on Sunday.

 
Weather Summary

Today we will see a chance of snow flurries in the afternoon with increasing clouds and southwest winds as we head into another stormy period of weather.  A cold front will be arriving after dark and responsible for bringing us back to winter. As this front passes through our area snowfall rates should be heavy with 4-10” expected tonight. With this new snow, winds will be strong from the west before moving to the northwest on Sunday. Snowfall rates will then decrease on Sunday with 1-4” expected, before another pulse of moisture arrives Sunday night under northwest flow. Check our next forecast on Monday to find out how we did and what more to expect.

 
Snowpack Synopsis

The likelihood of triggering an avalanche and the avalanche problems will be very different on Saturday versus Sunday.

 

For Saturday the snowpack is currently in limbo after having found a balance between the load of last weekends storm and underlying persistent weak layers. The snowpack is variable throughout the Elk Mountains and this makes Saturday's avalanche problem variable too. In many places the snowpack is shallow or lacks the right slab dynamics, making a persistent slab avalanche unlikely or non existent. Other areas will remain possible to human triggering of these persistent slabs. These possible areas will be where the snowpack is greater then 2 feet deep and mostly on above tree line slopes facing north, northeast and east.

 

By sunrise Sunday the snowpack will have seen a rapid increase in avalanche danger. With 4-10” of snow by Sunday morning and strong west to northwest winds. Natural avalanches will become possible and human triggered avalanches will be likely as snow continues to fall throughout the day. The primary avalanche concern will be windslabs 8” to 3 feet deep on near and above treeline slopes facing around the compass from north to east to south to southwest. These slabs will be most problematic where they build on near surface facets or areas the the snowpack is shallow and faceted to the ground. These snow surfaces are unevenly distributed and will make them harder to track. Secondary, where these winds slabs build over 12” deep they will be adding stress to persistent slabs on north to northeast and east aspects. Natural avalanches will be possible on these slopes as windslabs continue to build through Sunday and would be large enough to bury or kill a human. Some observations of these similar slabs can be seen here from last week's storm.

Travel Advice

Saturday will be an excellent day to get out and plan safe areas to ski Sunday's powder. Look for areas near and below tree line that are protected from wind and windslab development. If you are only getting out Sunday these same slope characteristics should be your destination and offer excellent/safer skiing. Also on Sunday, be mindful crossing below northerly and easterly above treeline slopes that could see natural avalanche activity.

 

This advisory expires Sunday, 11/23 at midnight.  The next advisory will be issued on Monday morning by 7 a.m.