Observations

Avalanche in Lip 02/21

February 21, 2021 at 1:00 PM
Name: Chris Wu| MWAC
Location: Lip Avalanche

An avalanche of the Lip was reported to MWAC at 12:40 pm. The reporting party did not see the slide occur, was not sure of the trigger, and did not have equipment to search for a potentially buried transceiver. Before and after photos were later provided by another individual, putting the time of the slide between 11:50 and 12:25. Thanks to both parties for sharing information.

MWAC and Mount Washington Volunteer Ski Patrol staff entered the ravine to seek more information and clues of a potential burial. The toe of the debris reached the mouth of the ravine. Visibility was intermittent due to clouds and blowing snow, but the team did not see obvious signs of a human trigger. There were fresh ski and sled marks through the debris, but it is unknown whether these individuals were involved or present when the avalanche occurred.

A beacon search was initiated at the toe and no signals were detected while ascending the debris pile. A Recco device was also used, but did not turn up any signals. A second beacon search was completed upon descent, again with no signals detected.

The crown was estimated to be 3 ft tall x 100 ft wide and the avalanche ran about 500 vertical ft.
SS-U-R2-D2-O
SS: soft slab avalanche
U: unknown trigger, possibly NL (naturally caused by loose snow avalanche above). It is also possible that the slide was triggered from below by a skier/sledder, based on the fresh tracks on the debris.
R2: Small relative to path
D2: Could bury, injure, or kill a person
O: Avalanche released within old surface, at interface between recent snow and crust from 02/16 storm.

Another slide was also reported in Gulf if Slides. These events demonstrate that recent snow and the resultant wind slabs are not well bonded to the icy crust below. Expect this issue to continue tomorrow, with 1-3″ of new snow and 50+ mph wind from the west in the forecast.