Avalanche Forecast

Archived

Feb 8th, 2019–Feb 9th, 2019

Alpine

Natural and human triggered avalanches likely.

Treeline

Natural and human triggered avalanches likely.

Below Treeline

Natural and human triggered avalanches likely.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches possible, human triggered probable.

Regions

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Travel in avalanche terrain is not recommended as avalanches will be life-threatening. Stay off of steep slopes and don't linger near or under any slope steeper than 30 degrees. You could trigger avalanches from far away or from the bottom of overhead slopes.

Discussion

Snow and Avalanche Discussion

Any of today's avalanches could be big enough to bury or kill you. Avoid all open slopes steeper than 30 degrees. In addition to wind slab and persistent slab avalanches, loose dry avalanches will be running naturally and could be dangerous. The most dangerous parts of the zone will be in the Wenatchee and eastern Entiat Mountains and east of Highway 97.

This is the biggest single storm to impact the zone this year. The weight of all the new snow is stressing underlying weak layers. Expect snow to continue through Saturday with up to 2 feet of total accumulation. If over 1 foot of snow accumulates in low valleys, avalanches may be possible in unusual places like on roofs and steep lowland slopes. Be aware of your surroundings and ask yourself, "Am I in avalanche terrain? Could the snow slide?"

Snowpack Discussion

Regional Synopsis coming soon.

Problems

Wind Slabs

Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind 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.

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.