Crazy remote triggering

CBAC 2020-21 Observations

Zone: Southeast Mountains

Location: East River

Date of Observation: 12/15/2020

Name: Zach Guy


Subject: Crazy remote triggering

Aspect: East

Elevation: 9100 – 9500′

Avalanches: Remotely triggered two small slab avalanches (about a foot thick, 20 feet wide, ran 30 to 50 feet).  One of the slides we triggered from 1200′ away! I watched the cracks connect and the feature slide in pure disbelief.  We also got a number of similar slopes to shatter with cracks and slump, but not move, mostly remotely triggered again.

Weather: Light to moderate northerly wind channeling down valley. Partly cloudy skies

Snowpack: About 10″ or so of settled storm snow over the 12/10 interface, which was decaying surface hoar on facets here. Recent and ongoing northerly winds had redistributed the snow into a patchy network of stiffer slabs (4F). We produced collapses in most areas where there was wind stiffening or loading. They seemed localized, but then we got a few collapses that produced cracking and avalanches from surprisingly long distances away. Surface hoar does some crazy things.  The slabs were small and easy to recognize, but we avoided riding above terrain traps where a small avalanche could push you into trees.