We have been finding small wind slabs and large wind drifts near the ridgetops on multiple aspects over the last week. Winds have swirled around the compass from S/SW to N/NW and have been sculpting and transporting the light density snow that has accompanied the last 2 storms. Yesterday we observed active loading on the backcountry terrain north of Tamarack Resort. Over the next 12-24 hours we will see winds continuing to gust in the upper elevations into the mid 20 mph range creating another round of wind slabs at or near the ridgelines. Be aware of crossloaded areas on smaller terrain features and watch out for obvious clues like cracking or hollow sounding/feeling snow under your skis or track.
Most of our mid elevation reporting sites picked up 5-7 inches of new snow in the last 24 hours. Expect to see 10 plus in the upper elevations, with over a foot by Christmas afternoon. Be cautious of the interface between the older, firm snow which was downright slick on some wind scoured upper elevation slopes, and the new snow above. On wind protected slopes the new snow may be resting on a newly formed layer of Surface Hoar which is a very weak layer. Anticipate soft storm slabs of up to 10 inches on terrain steep enough to slide today.
There are a number of great beginner avalanche classes coming up for both skiers and snowmobilers. Be sure to check out 'local classes' or upcoming events under the Education tab at the top of the forecast page. If you already have the basics down and are ready to take your Level One, skiers and snowmobilers can find classes this winter around the state, don't make excuses, just do it! Make staying safe while playing in avalanche terrain a New Year's Resolution!
We toured out of bounds at Tamarack Resort yesterday and found moguls on a lot of steep north facing terrain...the same terrain that is harboring the weakest spots in the snowpack. We found a strengthening slab overlying the facets near the ground on multiple aspects as well as some upper snowpack instabilities including the grauple layer from the warm storm 2 weeks ago. Overall strength was improving but there still exists a possibility of triggering a potentially fatal slide on shallow or rocky terrain. Our pit tests showed failures that were hard to initiate but provided very quick and clean shears in the faceted snow near the ground. Moderate verging on strong winds were easily moving the 2-3 inches of new snow and loading Northerly aspects throughout the day.
Most of our local Snotel sites and the ski areas are reporting 5-7 inches of new snow overnight at the 6500 ft level. Winds were easily moving snow yesterday and will be gusting into the mid 20's today. Snow will continue through the day today and then taper off tonight with cloudy skies and a chance of snow before noon on Christmas Day. The upper elevations could pick up an additional 3-6 inches before that happens.
This avalanche advisory is provided through a partnership between the Payette National Forest and the Payette Avalanche Center. This advisory covers the West Central Mountains between Hard Butte on the north and Council Mountain on the south. This advisory applies only to backcountry areas outside established ski area boundaries. This advisory describes general avalanche conditions and local variations always occur. This advisory expires at midnight on the posted day unless otherwise noted. The information in this advisory is provided by the USDA Forest Service who is solely responsible for its content.