Avalanche Forecast

Archived

Dec 30th, 2018–Dec 31st, 2018

Alpine

Natural avalanches unlikely, human triggered possible.

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.

Below Treeline

Natural avalanches unlikely.

Regions

Stevens Pass.

Steer clear of wind slabs near and above treeline, where slabs a couple of feet thick may have formed. Have a great day, but don’t let blue sky fever cloud your decision making process.

Discussion

Snow and Avalanche Discussion:

This past storm brought about 17” inches of new snow with 3.3” of water equivalent to Stevens Pass. It rained up to at least 5200ft during the storm, then a cold front with strong winds blew through as the snow accumulated. We are left with fresh, cold snow over a refreezing wet snow crust, and some deep wind drifts. During the day on the 30th, ski area snow safety teams were able to trigger wind slabs big enough to injure, bury, or kill a person with control work.

Snowpack Discussion

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.

Loose Wet

Loose Wet avalanches are the release of wet unconsolidated snow or slush. These avalanches typically occur within layers of wet snow near the surface of the snowpack, but they may quickly gouge into lower snowpack layers. Like Loose Dry Avalanches, they start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-wet avalanches include point-release avalanches or sluffs. Loose Wet avalanches can trigger slab avalanches that break into deeper snow layers.