Observation Date
2/12/2021
Observer Name
Bill Nalli
Region
Salt Lake » Big Cottonwood Canyon » Silver Fork » West Bowl
Location Name or Route
West Bowl Silver Fork
Comments
The snowpack in the cental cottonwoods is finally getting deep enough to stop the faceting process near the ground. Stopping this process and healing the weakness are two different things however. That is going to take much longer, if it ever happens this winter. There is now a dense thick slab above the well documented weak layers deeper in the snowpack. It may be hard to trigger but if one is to find a deficit zone or an area where the slab is thinner, the weight of a rider is capable of triggering a very large avalanche.
Closer to the surface, the new/old snow interface has some small grain facets that formed over the last week. Now buried 6 to 10 inches below the newest snow, it was producing clean shears in stability tests and localized cracking on slopes steeper than 35 degrees. A slight density inversion along with some noon-time graupel is adding to this new snow instability. Pic 1 is a small skier triggered new snow avalanche on south facing Emma 2 in early am and pic 2 is cracking while skiing later in the day on an adjacent slope. Pic 3 small graupel.
The cornices along the Emma Ridge above West Bowl have grown much larger in the last month. We kept our distance because of the poor visibility, large numbers of people out and about, and greater potential for this kind of a big trigger to reawaken the deeply buried weaknesses below. I'm getting a sense that it is wise to reevaluate our normal safe zones and create an extra margin between you and any steep slope facing northwest thru north to east.
Today's Observed Danger Rating
Considerable
Tomorrows Estimated Danger Rating
High
Coordinates