Avalanche Forecast
Regions: Mt Hood.
Happy New Year! New Year's Day proves to be glorious sunshine but watch for recently formed wind slabs at higher elevations, especially near ridges. These wind slabs are healing but it may still be possible to trigger an avalanche on steeper wind-loaded slopes. Wind slabs at lower elevations will be harder to trigger but still possible on the right steep open slope or in a recently cross-loaded gully.
Discussion
Avalanche and Snowpack Discussion
Following rain and freezing rain Saturday, 10-12 inches of snow accumulated Saturday night and Sunday with strong west to northwest winds slowly easing during the day on Sunday. Mt. Hood Pro-patrol found fresh but stubborn wind slabs up to 2' deep near treeline. More importantly, wind slabs had developed on unusual aspects, cross-loaded slopes and formed on open slopes below treeline. Winds had scoured ridges to the most recent firm icy crust in many areas. We have no recent observations from above treeline due to the recent stormy conditions.Â
Snowpack Discussion
Updated Regional Synopsis coming soon
Avalanche Problems
Wind Slabs
Wind slabs formed over the weekend are gaining strength, but have not fully healed. Backcountry travelers and local professionals reported finding wind slabs in unusual locations such as low on the slope and in areas often wind-stripped. You may still trigger wind slabs on convex rollovers, near the sides of cross-loaded gullies, and on wind drifted snow well below ridgeline. In some locations, wind drifted snow may sit over a layer of buried surface hoar. In these locations, an avalanche may propagate widely and surprise you by extending long distances.
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.
Wind Slabs form in specific areas, and are confined to lee and cross-loaded terrain features. They can be avoided by sticking to sheltered or wind-scoured areas..
Wind Slab avalanche. Winds blew from left to right. The area above the ridge has been scoured, and the snow drifted into a wind slab on the slope below.
Wind slabs can take up to a week to stabilize. They are confined to lee and cross-loaded terrain features and can be avoided by sticking to sheltered or wind scoured areas.
Aspects: All aspects.
Elevations: All elevations.
Likelihood: Possible
Expected Size: 1 - 1