Avalanche Forecast

Archived

Dec 11th, 2018–Dec 12th, 2018

Alpine

Natural and human triggered avalanches likely.

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 unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Regions

Mt Hood.

Dangerous avalanche conditions will persist on Wednesday due to recent snow and wind. Avoid exposure to avalanche terrain capable of producing large avalanches. Below treeline, due to early season conditions, small avalanches have a greater potential for injury due to exposed rocks and vegetation.

Discussion

Discussion

Prior to Tuesday's warm storm, reports of persistent weak layers in the upper snowpack were not found to be reactive by Mt. Hood Meadows patrol during control work or in snowpack tests. Keep this recent layering in mind and look for weak snow in the upper snowpack below the most recent storm snow. If avalanches do occur on this layer, they may act in surprising ways including remote triggers and wide propagation.

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.