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At upper, mid and lower elevations
High hazard for wet loose avalanches on slopes steeper than 35° and in rocky areas. On Friday many wet slides were occurring naturally throughout the day, and were sensitive to human triggers. These conditions have not improved as temperatures at 4500′ remained above freezing overnight. Travel in and near avalanche terrain is not recommended.
At upper elevations (above 3500′)
Considerable hazard for wet slab avalanches 6 inches to 2 feet deep in very specific locations. These pockets of old wind loaded slab exist at or near ridgelines, sit on weak faceted snow and are becoming saturated with rainwater. Additionally they could be more sensitive as water percolates to their bed surfaces and breaks down their bond to the underlying snowpack.
Click here for a description of low, moderate, considerable, high and extreme hazards using the North American Avalanche Danger Scale.
AVALANCHE CONCERN 1:
It’s not April, so it’s not a foolish joke. It’s December in Alaska and we have a significant warming trend with the addition of 1/2 an inch of rainwater. As of Thursday, December 5th, at 7am the temperature at the Marmot weather station at 4500′ remained at or above 32°F through this morning. The entire snowpack is becoming saturated with water and approaching isothermal status. Check out the temperature profile in the snow pits. Temperatures are predicted to stay on the warm side today with a high of 31°F at 4000′. Temps tonight are predicted to drop to a low of 23°F at 4000′ which will help to start to freeze the snowpack and improve stability for Sunday.
The loose dry powder we enjoyed last weekend has changed. Water being absorbed and percolating through the snowpack is breaking down bonds in the top 2-3 feet of the snowpack. In areas 35° and steeper wet loose avalanches are very sensitive to human triggers and are naturally releasing down to the ground or to the melt-freeze base in the weaker, rocky zones. Expect slides to entrain significant amounts of snow, and while they move slower than their dry slab brethren, they can still catch you and bury you deeply. Avoid steeper terrain (35° and above), especially near rock bands, and avoid areas with terrain traps in the runnout. Poor visibility today will make it dangerous to travel under and near steep slopes where the runnout of an avalanche may go further than you expect. Stay clear. Pictures
AVALANCHE CONCERN 2:
In very specific areas, there are old hard slabs and mostly soft slabs sitting on weak, faceted snow. These are found at or near ridgelines above 3500 feet. These formed in the middle of last week with a small spell of strong gusty wind. They are generally small in scale, but big enough to injury and possible bury a person. These have been stubborn to trigger, but with warmth, the added weight of rain and free water percolating and lubricating the bed surface, expect these pockets to be touchy and easily human triggered. Avoid wind loaded pockets near ridgelines above 3500′ on slopes 40° and steeper.
As the weather cools into Sunday, expect the hazard to drop sharply as the snowpack freezes and literally “ceases up”. This weekend the blessing is in disguise, but as soon as the snowpack gets cold again it will be an excellent, impenetrable base. Watch the temps carefully for stability to increase with a significant drop in temperature. For now, steer clear of the unstable paradigm, wait for the sun to come out, and for generally better days ahead. If you do get out, stay off the steeper terrain and clear of the runnout of steep slopes. Its a good time to enjoy the XC trails, the snowmachine corridors or just a hot cup of coffee in front of the fireplace.
Have a safe weekend,
–Jed Workman, Allie Barker
If you are out and about HP and see an avalanche or have a snow observation, please share it with us by clicking on these links or under the observations tab in the menu bar or email us at email@example.com