Avalanche Forecast

Strong winds formed stubborn, new slabs this weekend. Reports from the field indicated seeing wind loading in unusual locations including much further down the slope than normal and on cross-loaded gully features. Wind slabs like this can be tricky. They often don’t seem very reactive. This can lure you out onto the slab. Using visual clues can help you identify and avoid wind loaded slopes. If you see fresh cornices, wind drifted snow, or feel firm, hollow, surface snow, wind slabs are nearby. We may see these slabs grow deeper at higher elevations, as moderate north winds transport more snow Monday.

If you use the nice weather to travel to higher elevations or into more remote areas take time to stop and observe the snow. Due to stormy weather we have not received any information from higher elevations in quite some time.  

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.

If the sun comes out Monday, you will see loose snow avalanches on steep, rocky, and sunny slopes. Don’t get surprised by this easy to anticipate avalanche problem. If the sun comes out, you see rollerballs, or you observe new fan shaped avalanches avoid confining gullies and high consequence slopes where even these small avalanches can hurt you.

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. They generally move slowly, but can contain enough mass to cause significant damage to trees, cars or buildings. 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.

Travel when the snow surface is colder and stronger. Plan your trips to avoid crossing on or under very steep slopes in the afternoon. Move to colder, shadier slopes once the snow surface turns slushly. Avoid steep, sunlit slopes above terrain traps, cliffs areas and long sustained steep pitches.

Several loose wet avalanches, and lots of pinwheels and roller balls.

Loose wet avalanches occur where water is running through the snowpack, and release at or below the trigger point. Avoid terrain traps such as cliffs, gullies, or tree wells. Exit avalanche terrain when you see pinwheels, roller balls, a slushy surface, or during rain-on-snow events.