Avalanche Observation, Tuckerman Ravine
By Helon Hoffer | Mount Washington Avalanche Center
Date of Observation: March 8, 2019 1:10 PM
Location of Observation: Tuckerman Ravine
Around 1pm, a skier triggered an avalanche on the steep skier’s right wall of Right Gully (HS-AS-R1-D1). This is a common spot for skiers to trigger avalanches in Right Gully because of the steep slope angle and the aspect of the slope changes from south to SE, directly in the lee of our prevailing westerly wind. The skier tried to ski cut the slope, but got nothing to move. Upon turning back, he was able to get the pocket of wind slab to release. The skier watched the slab break at his feet and was able to stay standing as the debris nice when the gully. Two people who were digging a snow pit below the choke were caught and carried around 25 feet. They were able to stand up and walk away.
Where this wind slab that formed at the start of the week exists, the structure consists of a slab that is 10cm-30cm of pencil hard snow, a thin (~5cm) weak layer of 4F snow, and a bed surface of pencil hard snow. In addition to the avalanche in Right Gully, tests today on various easterly aspects showed a propensity for propagation, moderate strength, and Q1 to Q2 shears.