Avalanche Forecast

You could trigger avalanches in the eastern portion of the zone and on steep, shaded slopes facing west through north through east. While deep persistent slabs are generally difficult to trigger, they are also hard to predict. They will give few warning signs before releasing. If you travel over the wrong spot, you could trigger a very large and dangerous avalanche. The best way to reduce the risk of this is a low likelihood, high consequence scenario is to minimize your exposure to terrain capable of producing large avalanches:

-Limit the amount of time you spend on or near slopes 35 degrees and steeper.

-Put an extra buffer of terrain between where you travel and where avalanches could start.

-Stay well out from under large avalanche paths and identify safer areas to stop and regroup.

Release of a thick cohesive layer of hard snow (a slab), when the bond breaks between the slab and an underlying persistent weak layer, deep in the snowpack or near the ground. The most common persistent weak layers involved in deep, persistent slabs are depth hoar or facets surrounding a deeply buried crust. Deep Persistent Slabs are typically hard to trigger, are very destructive and dangerous due to the large mass of snow involved, and can persist for months once developed. They are often triggered from areas where the snow is shallow and weak, and are particularly difficult to forecast for and manage. They commonly develop when Persistent Slabs become more deeply buried over time.

Deep Persistent Slabs avalanches can be destructive and deadly events that can take months to stabilize. You can trigger them from well down in the avalanche path, and after dozens of tracks have crossed the slope.

A snowboarder triggered this Deep Persistent Slab near treeline, well down in the path.

Deep, persistent slabs are destructive and deadly events that can take months to stabilize. You can triggered them from well down in the avalanche path, and after dozens of tracks have crossed the slope. Give yourself a wide safety buffer to handle the uncertainty, potentially for the remainder of the season.

Steer around wind loaded features and areas where the snow deep and thickly pillowed on slopes steeper than 35 degrees. Use caution on leeward slopes just below ridges.

Avalanches will be easier to trigger as you climb higher in the mountains. Strong wind and new snow from the past 3 days have formed slabs near and above treeline. If you trigger an avalanche in wind drifted snow, dig into deeper layers, resulting in a very large and dangerous deep persistent slab.

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.