This week, the upper elevations have been dominated by light to moderate mostly Northerly winds. These winds were able to move the 5 inches of light density snow around easily, and created soft wind slabs on multiple aspects before yesterday. Over the last 24 hours, winds have been out of the south , and we have picked up an additional 2 to 5 inches of snow that is available for transport causing for another new round of wind slabs. These new thin wind slabs caused isolated cracking and localized collapsing yesterday in low angle and wind loaded terrain. If you were to travel on steep wind loaded terrain today, these isolated/localized failures in the upper snowpack could propagate and take you for a ride.
In addition, you can still find the affects of the wind from the weekend and the end of last week. Most of the wind slab problems are going to be found on the northerly aspects where new slabs have been formed on top of older wind slabs. Watch for sculpted or stiff wind board on the windward aspects and rippled, chalky or hollow feeling/sounding pillows and drifts on steep leeward aspects. You should also be aware that some of the older wind slabs may be found well below the ridge lines on leeward terrain.
These areas are going to require careful evaluation now that new snow has begun to camouflage these older slabs. Areas with stiff wind board are going to be shedding snow as well as the new snow starts to accumulate. Practice safe travel protocols, and expose only one person at a time in wind loaded avalanche terrain. Pay attention to changing conditions over the next few days, the snowpack is going to be under stress as we add additional snow and weight from this warm Pacific storm.
If snowfall exceeds forecast today, and/or you find isolated areas not impacted by the winds, there is a chance of finding storms slabs today. If found they should be fairly thin, with the primary danger being where one of these very isolated slabs could take you if you were to cause an avalanche.
Thanks to all that participated in this years Introduction to Avalanches. We had 28 eager skiers and snowmobilers who attended Friday night's classroom portion, and then braved the cold yesterday morning to practice rescue and learn about the snowpack.
We have an all female Introduction to Avalanches class for Skiers and Snowboarders coming up on January 21st at Tamarack.
The Friends of the Payette Avalanche Center (FPAC) needs YOU! We are in desperate need of more user support and financial assistance. The avalanche forecast is not a guaranteed service, and is in jeopardy of dwindling down to only a couple of days a week in the near future. Please help if you can by clicking the DONATE tab above. If you value this life saving information, make a donation or help the FPAC in raising funds for the future.
Yesterday afternoon we found fresh wind slabs developing on north and northwest aspects from the new snow and light to moderate winds. As we broke trail out to a study pit location, I had isolated shooting cracks and localized collapsing. All of which was due to the new/thin wind slab sitting on older low density powder. In out study pit location on a northwest aspect at approximately 7,700 feet we found 110 cm snowpack that had good stability and no major layers of concern.
Overnight the mountains around the advisory area picked up 2 to 5 inches of new snow accompanied by moderate winds in the teen's out of the south southwest. Today expect to see an increase in winds and precipitation as the day progresses. The upper elevations will see another 2 to 6 inches of new snow today with winds starting out in the teens, and blowing 20's with gusts in the high 30's by late afternoon.
This avalanche advisory is provided through a partnership between the Payette National Forest and the Friends of 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.