Avalanche Forecast

Thursday will be a day of transition out of one storm before another arrives Friday. Although recent storm snow is settling, it’s not open season yet. Pay attention to wind transported snow. Reports from the Crystal backcountry suggested that strong winds built fresh, shallow wind slabs near treeline today that were sensitive to human triggers. Identify signs of wind transport such as cornices, stiff and textured snow surfaces and pillow-like drifts. Avoid lee slopes steeper than 35 degrees where you see evidence of wind transport.

With the high snowfall totals recently, especially near Paradise, storm slabs may still linger on convex rolls and unsupported slopes. Steer around convexities, unsupported slopes and slopes steeper than 30 degrees where you may still find storm slab instabilities.

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.