Avalanche Forecast
Regions: Olympics.
Shallow new wind or storm slab avalanches are possible on the highest peaks in the Olympics by Friday afternoon.
Detailed Forecast
An approaching Pacific frontal system should increase cloud cover for the Olympics Friday morning and bring a significant uptick in SW winds with light rain and snow developing by mid-day. Significant new snow and rain should hold off until later Friday afternoon for the Olympics, minimizing new storm snow problems during the daylight hours.Â
Shallow new wind or storm slab avalanches are possible on the highest peaks in the Olympics by Friday afternoon.Â
Snowpack Discussion
A broad upper trough moved over the Northwest last weekend through early this week causing periods of light snow for the Olympics at low snow levels although only very minor new snowfall accumulated near Hurricane Ridge. On Wednesday and Thursday, clear skies transitioned to scattered afternoon showers with light and spotty new accumulations. April freezing levels have been very low compared to most of the winter, averaging about 4-5000 feet thus far.
Unfortunately, we are still a long way off from building a meaningful snowpack in the Olympic mountains as we head further into spring. Â
No recent snowpack observations have been received from the Olympics and most areas near and below treeline in the Olympics do not have enough snow to cause an avalanche danger.
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: Alpine.
Likelihood: Possible
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.
Elevations: Alpine.
Likelihood: Possible
Expected Size: 1 - 1