Avalanche Forecast

Archived

Dec 23rd, 2019–Dec 24th, 2019

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Regions

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Dangerous avalanche conditions are lingering after a major winter storm stressed older weak layers in the snow. Use caution near slopes 35 degrees and steeper and avoid lingering below steep terrain. Put a large buffer of space between where you travel and any slopes that are steep enough to slide.

Discussion

Washington Pass picked up over 3 feet of snow and 3.2" of water equivalent between Thursday afternoon and Saturday. Observers reported large natural avalanches in Silver Star creek, the Delancy Ridge area, on a northwest aspect of Silver Star Mountain, and a northeast aspect of Hinkhouse peak. Observers witnessed an avalanche run on Saturday around noon on a north aspect of Peak 6460ft near Silver Star creek. On Sunday, an observer near Vasiliki Ridge reported collapses that covered areas as wide as 30 feet.

Snowpack Discussion

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

Problems

Persistent Slabs

Persistent Slab avalanches are the release of a cohesive layer of snow (a slab) in the middle to upper snowpack, when the bond to an underlying persistent weak layer breaks. Persistent layers include: surface hoar, depth hoar, near-surface facets, or faceted snow. Persistent weak layers can continue to produce avalanches for days, weeks or even months, making them especially dangerous and tricky. As additional snow and wind events build a thicker slab on top of the persistent weak layer, this avalanche problem may develop into a Deep Persistent Slab.