Observation: Meadows

Observation Date
1/16/2019
Observer Name
Catino
Region
Salt Lake » Big Cottonwood Canyon » Silver Fork » Meadows
Location Name or Route
Silver Fork - Meadow Chutes
Red Flags
Red Flags
Recent Avalanches
Heavy Snowfall
Wind Loading
Cracking
Poor Snowpack Structure
Comments
Manageable and yet tricky at the same today. Broke trail towards Football Fields with not much wind effect and little action within the storm snow, while hearing about the activity in LCC. Two points worth noting from higher in the drainage: the graupel that fell late morning provided a change in snow density but without the wind it lacked cohesion and slab for any reacitivty, also NE facing slopes near the Football Fields had weak snow that sat underneath a stiff windslab - this was about 90cm below the suface. We skied East and placed our skinner up the SE aspects.
Upon our exit down the tube, I observed a natural (which likely occured during the storm) that connected along the NE side of the wall - likely from the SW winds. The soft slab ran through the bottom third of the tube. When I saw this natural activity I pulled onto the SE side and stopped, noticing some uneasy snow underfoot. I then put in a small ski cut to the next island of trees and easily pulled out the storm snow, and then again as I wrapped a longer section - ski cutting it away as I moved to safe zones.
The weak interface seemed to be the rime or freezing rain layer from yesterday, which was easily observed from my goggles yesterday while skiing around upper BCC. The photos below show the storm slab, with rime layer acting as the bed surface. This layer wasn't reactive higher up, and I'm wondering if it was a bit thicker down lower where I got a bunch of easy activity. The elevation where things became unglued in Silver Fork was around 8,800 feet. It was all very manageable, but of note below the rime layer on the SE was some weaker snow, then a suncrust, then very weak faceted snow underneath the sun crust. With more wind, snow, and water these thin snowpack areas may produce some large avalanches.
Photos below show the natural avalanche in the tube, easy ski cut slides in the storm snow, and the above noted layers of concern with facets below sun crust.
Today's Observed Danger Rating
Moderate
Tomorrows Estimated Danger Rating
Considerable