February 19, 2020

Avalanche Danger Update

Very dangerous avalanche conditions exist in the Western Chugach Mountains and Chugach State Park.  High avalanche danger is expected through Thursday.  Travel in avalanche terrain is not recommended.  Natural avalanches are likely, and human triggered avalanches are very likely.

Strong wind Monday, followed by significant snowfall Tuesday and Wednesday, with strong wind forecast again Thursday; has drastically increased avalanche danger in the greater Anchorage area.

Keep in mind that many popular trails and recreation areas around Anchorage are exposed to potentially dangerous avalanche terrain.  Considering how dangerous conditions are expected to be through Thursday, natural avalanches have the potential to affect popular trails like Powerline, Flattop, and the O’Malley gully in the Glen Alps area; Falls Creek, Bird Creek, and Penguin in the Turnagain Arm area; South Fork Eagle River near Eagle and Symphony Lakes; and Crow Pass from both Girdwood and the Eagle River Nature Center.

This list of trails that may be affected by high avalanche danger is not exhaustive.  If you are planning on recreating in or around the mountains in the coming days, make sure you know how to identify and avoid potentially dangerous avalanche terrain.

Even if you are on flat ground, beware of steep terrain above you!  Large and potentially deadly avalanches have the potential to descend from steep terrain thousands of feet above and run out to flat terrain (e.g. north-facing avalanche paths along the ridge between Flattop and Ptarmigan on the south side of the South Fork Campbell Creek valley that have the potential to cross the Powerline trail).

Multiple buried persistent weak layers (e.g. basal facets and depth hoar from the early season, extensively faceted snow from the very cold and dry January) are widespread in the Western Chugach Mountain snowpack.  Stress from new snow and wind may produce large avalanches that fail on these layers, as well as other weak layers and interfaces nearer the surface.