Avalanche danger may be higher than posted in areas that receive more snow than forecast.
Confidence
Fair - Intensity of incoming weather systems is uncertain on Thursday
Weather Forecast
An intense low pressure system continues to churn in the Gulf of Alaska.Thursday: The first in a series of systems will hit the region . Expect up to 5 to 10cm of snow at higher elevations. Moderate southwesterly winds at ridgetop will persist through the day. Freezing levels will rise to 1000m.Friday: A brief lull with light precipitation and moderate southwest winds at ridgetop. Freezing levels dropping to 700m.Saturday: Likely moderate snow with strong winds from the southwest as the next system hits the region.
Avalanche Summary
No recent avalanche have been reported
Snowpack Summary
Snowpack depths vary greatly across the region with 160cm at treeline in the Cascades but 50 cm along the Duffy. Terrain below treeline is still mostly below threshold for avalanche activity.Surface hoar has been growing over the last week in protected locations near tree line while the cold temperatures have driven faceting throughout the snowpack.A few crusts can be found near the ground, especially at higher higher elevations. Cold temperatures may have weakened the snow around these crusts - especially in alpine areas with a thinner snowpack such as moraines.
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.
Deep Persistent Slabs
Deep Persistent Slab avalanches are the 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. 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.