Avalanche Forecast

Archived

Jan 20th, 2020–Jan 21st, 2020

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

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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The avalanche danger will increase throughout the day. By Tuesday afternoon, you may be able to trigger small avalanches in the new snow at upper elevations. Check how well the new snow is bonded to old surfaces, and use caution on slopes steeper than 35 degrees if you find six inches or more of recent snow that slides easily.

Discussion

On Monday, Ski Patrol at Mission Ridge triggered a handful of avalanches on leeward, wind loaded slopes with crowns up to 1 foot deep.

While new snow accumulation is forecasted to be light on Tuesday, there is some uncertainty. Snow will add up throughout the day, but should only accumulate around 3 inches by dark. You may find deeper snow totals and drifts at higher elevations. Expect moderate snowfall and gusty winds with up to another 5-8" of accumulation Tuesday night, especially near the Cascade Crest. Expect an increase in avalanche danger after dark on Tuesday.

Snowpack Discussion

New Regional Synopsis coming soon. We update the Regional Synopsis every Thursday at 6 pm.

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.