Observations

Avalanche crown face in Chute

January 30, 2021 at 1:00 PM
Name: Frank Carus| USFS MWAC
Location: Chute, Tuckerman Ravine

I climbed up to check on the bed surface and slab characteristics of recent avalanche activity in Chute. I found a 35cm (14″) thick slab that ran on the 157 mph wind hammered bed surface with debris and volume that indicates a D2 avalanche that may have been capable of burying a person. The slab was increasing dense bottom to top with fist hardness snow at the bottom with finger plus snow on the surface. The crown ran wall-to wall in the middle start zone and was remarkable uniform in thickness. This slab configuration was the same as the snow structure found a few minutes later in Left Gully. Seems likely that Left Gully did not avalanche in that cycle, probably due to the lower angle and terrain configuration. I was at the mouth of Chute on Thursday afternoon, prior to the avalanche, and observed active, natural sluffing as 20 mph winds pushed the 4-5″ snow down the slope. It seems likely that this avalanche occurred during the 6-8 hour period of 50 mph wind overnight Thursday due to the small amount of refilling of rounds in front of the crown face. Crown width was approximately 35 meters (110′) wide. One other, much smaller, crown line was observed below the cliff band in Lower Snowfields that seems to be from the same event.