Parts of the PAC advisory area saw sustained winds in excess of 35 mph on Monday. Gusts climbed over 50 mph. With the amount of snow we received, that equals some serious wind transport. Be aware that you could trigger a shallow or deep wind slab on upper elevation wind loaded slopes for the next few days. Cold temperatures do a great job preserving wind slabs and other weaknesses in the snowpack. You will be able to spot wind affected slopes literally from a mile away, look for sculpted or pillowed features as you make your terrain choices.
The West Central Mountains have recieved over 4 feet of snow in the last 7 days. Overall the bonds between these different storm layers are pretty good, but we are still finding signs of instability at density changes within all this new snow. We found over 300cm (just about 10 ft) of snow yesterday in a wind loaded N facing bowl near Fisher Creek Saddle. Throughout the advisory area, we are seeing snow depths similar to what we would normally see much later in the season with most upper elevations in the 6-7 foot range. Bottom line is that you may still trigger one of these instabilities in the new snow on unsupported, steep rollovers or other convex slopes. See the pit tests from yesterday for depths and scores.
Loose dry avalanches are a good problem to have, they mean you have deep, dry snow that is soft enough to move around when disturbed...most of the time these "sluffs" are pretty manageable. We saw a lot of moving snow yesterday on steeper slopes and while they are moving relatively slow and small right now, they could still push you off course on a sled or skis. Be aware of sluff potential and your options if you are riding or sliding in steep, confined terrain or terrain with obstacles or cliffs below you.
George and I took advantage of the mostly clear skies and checked out the steep terrain north of Granite Mt, Hard Creek, near Duck Lake and throughout the headwaters of Fisher Creek yesterday. Conditions were much better than we anticipated earlier in the week based on the storm totals and wind that our advisory area got hit with. We saw little evidence of the natural storm snow avalanche cycle that we had anticipated. Our snowpits showed relatively good bonding within the new snow layers with some failures at density changes within the new snow layers, because of the lack of cohesion within the new snow these weaknesses lacked the ability to propagate in our Extended Column Tests or during sled cuts on steep rollovers. Based on the Red Flags we saw waving at the beginning of this storm cycle we got pretty lucky as the new snow piled up. Bear in mind that you may still encounter some pockets of touchy wind slab and utilize good travel protocols: one at a time on slopes, keep your eyes on your partners and ride or ski with all of your avy gear on your body.
|0600 temperature:||no data deg. F.|
|Max. temperature in the last 24 hours:||deg. F.|
|Average wind direction during the last 24 hours:|
|Average wind speed during the last 24 hours:||mph|
|Maximum wind gust in the last 24 hours:||mph|
|New snowfall in the last 24 hours:||inches|
|Total snow depth:||inches|
Our powder forecast continues to look great through Christmas Eve with high pressure building over the weekend and pushing the next few storms to the South of the West Central Mountains. With moderate accumulations and cooler temperatures over the next 48 hours, the new snow is going to be blower dry.
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.