Avalanche Forecast

Archived

Feb 12th, 2019–Feb 13th, 2019

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches possible, human triggered probable.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Regions

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Deep new snow combined with strong winds and warming has created dangerous avalanche conditions requiring conservative terrain choices Wednesday. Avoid steep slopes greater than 35 degrees, especially higher terrain that received wind deposited snow where you are likely to trigger avalanches. Avalanches could be large and run far and fast.

Discussion

Snow and Avalanche Discussion

Since Sunday morning an impressive 3-5 ft of new snow has fallen in this zone, with over two feet of new snow in 24 hrs as of Tuesday morning! Much of the storm snow has fallen at cold temperatures with gradual warming and some strong winds Monday night. All this storm snow is sitting on a hard crust and in areas may be poorly bonded with faceted crystals on the crust. This persistent grain type exists in adjacent zones, but there are limited observations in this zone. There were natural and triggered slab releases in the storm snow Tuesday in the Crystal area with some slides running fast and far. It will take some time for these dangerous conditions to stabilize requiring conservative travel.

Snowpack Discussion

New Regional Synopsis coming soon.

Problems

Storm Slabs

Storm Slab avalanches are the release of a cohesive layer (a slab) of new snow that breaks within new snow or on the old snow surface. Storm-slabs typically last between a few hours and few days (following snowfall). Storm-slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.