Avalanche Forecast
Regions: Olympics.
Watch for developing storm slabs, wind slabs and possible buried surface hoar, especially in areas receiving the heaviest snowfall with the strongest winds, such as at higher elevations. Choose very conservative terrain.
Detailed Forecast
Increasing storm conditions Saturday. Light rain and snow should increase early Saturday through the day, becoming moderate to possibly heavy, along with increasing westerly crest level winds. This should build unstable storm and wind slab layers through the day, with wind slabs spreading to NE-SE facing exposed terrain, especially below ridges by afternoon.Â
Expect dangerous avalanche conditions near and above treeline, especially by late Saturday afternoon. Careful snowpack evaluations, cautious routefinding and conservative decision-making will be essential Saturday.Â
Snowpack Discussion
This is the first backcountry avalanche forecast for the Olympic zone this season!
NWAC observer Tyler Reid confirmed that as of Friday, 12-26, there was now sufficient snow to produce avalanches and get someone in trouble if in the wrong spot. There is still a very shallow snowpack at elevations near 5000 feet, however, in the NTL zone sufficient coverage now exists as paths fill in.Â
Have a look at Friday's video observation by Tyler Reid:
Avalanche Problems
Storm Slabs
Release of a soft cohesive layer (a slab) of new snow that breaks within the storm snow or on the old snow surface. Storm-slab problems typically last between a few hours and few days. Storm-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.
You can reduce your risk from Storm Slabs by waiting a day or two after a storm before venturing into steep terrain. Storm slabs are most dangerous on slopes with terrain traps, such as timber, gullies, over cliffs, or terrain features that make it difficult for a rider to escape off the side.
Storm slabs usually stabilize within a few days, and release at or below the trigger point. They exist throughout the terrain, and can be avoided by waiting for the storm snow to stabilize.
Aspects: All aspects.
Elevations: All elevations.
Likelihood: Likely
Expected Size: 1 - 1
Wind Slabs
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: North, North East, East, South East, South.
Elevations: Alpine, Treeline.
Likelihood: Likely
Expected Size: 1 - 1