Size 4: Could destroy a railway car, large truck, several buildings, or a substantial amount of forest
Little Alaska (one of the north facing slopes across the valley south of the Pioneer yurt) looked like it had a recent very large avalanche. See attached picture. There were a number of size 2-3 avalanches seen in the area as well. They looked to be mostly on steeper, rocky, shaded slopes.
Signs of Unstable Snow
Did you see shooting cracks?
Did you experience collapsing or whumpfing?
Attached a picture of some of the isolated cracking seen on the steeper sections of our skin track on 2/5. This was near the pit we dug. We experienced a lot of whumpfing along this skin as well. We chose to ski on lower angle slopes (<30 degrees) for the duration of our yurt trip. When we skied out of the yurt on 2/7 we experienced additional whumpfing. I expect our weak layers will take a bit of time to heal.
Observed Avalanche Problem #1:
Dug a pit and performed a column test. The pit was at 9900 ft on a SW aspect. Slope angle was about 26 degrees. The weak crust layer that was buried by the storm at the end of January was about 2 ft deep and failed on the 2nd wrist tap. The slab then slid without having to apply much force. I suspect we would have triggered a size 2 or 3 slab avalanche on this weak layer had we ventured into steeper terrain.
Observed Avalanche Problem #2:
Deep Persistent Slab
Dug a pit and performed a column test. The pit was at 9900 ft on a SW aspect. Slope angle was about 26 degrees. The weak facet layer at the ground failed on the 3rd shoulder hit. I suspect an avalanche triggered in the top half of the snowpack has a good chance of stepping down to the weak layer on the ground.
Observed Avalanche Problem #3:
As the report has been saying, the consistent winds have been loading a lot of slopes. We saw signs of heavy wind loading on most slopes, especially near ridge lines.