Observation Date: 01/10/2020

Route/Location:
Hollywood Bowl, Lost Trail Powder Mountain

Weather:
Overcast, snowing, temps in single digits.

Wind:
10-15 mph SSW

New Snow: 12+”

Avalanche Activity:
On Friday morning at appx 9am , 3 patrollers ran a snow saftey/assesment route in Hollywood Bowl at Lost Trail. There had been 18″ of new snow, and appx 3′ of snow above a layer of depth hoar on the ground. The Hollywood Bowl cornice itself had a significant wind deposit, and we knew from past experience this was unstable. We approached with extreme caution, staying in safety zones, and dug two pits, with different, but no consistant indicator on the ECT tests. Still concerned with the stablility, we made cautious ski cuts from an adjacent ridge where we felt safe. As we watched above and below, one skier was able to cause a small collapse in a gully below him, which, in a matter of seconds, caused a sympathetic collapse of the entire Hollywood Bowl, going to the ground. We rated the avalanche as one of the largest we have seen there, a R4 D4.

Other Comments:
Images are available on Lost Trails website.
Appx 6-8 ft crown face, deposition depth at the bottom 9′

Observer: Robert Griswold