Avalanche Forecast
Regions: Olympics.
Fresh wind slab will be the primary avalanche problem on Tuesday. Look for signs of recent wind loading and don't assume a lack of natural avalanche activity means a slope can't be human triggered!
Detailed Forecast
A weak front will approach the area Tuesday spreading high clouds over the area in the afternoon with perhaps some very light rain and snow beginning during the late afternoon. After a cool start Tuesday morning freezing levels should moderate a bit into the afternoon.Â
Fresh wind slabs in the near and above treeline bands found mainly on lee easterly aspects will be the main avalanche problem Tuesday. Watch for signs of firmer wind transported snow that indicate wind slab. Storm slabs should be more difficult to trigger and isolated on Tuesday since storm snow instabilities have had time to settle.Â
In much of the below treeline band there is not enough snow yet for avalanches.  Avalanche problems should be limited to the upper part of this elevation band.
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Snowpack Discussion
A great report was received via the NWAC Observations tab for Saturday for the Hurricane area. In summary pit tests gave only a low quality shears or collapses and an ECT test that did not indicate any propagation. Loose dry avalanches were indicated as the main concern.
On Sunday morning the Hurricane rangers reported 7 inches of new snow. They reported that a snowboarder on Saturday triggered a small loose dry snow avalanche on the Sunrise run, a steep slope that faces northeast at about 5200 feet.
No observations were submitted on Monday but another 4 inches accumulated above 5000 feet in the Hurricane Ridge area with generally light WNW winds recorded at the NWAC weather station.Â
Avalanche Problems
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, North West.
Elevations: Alpine, Treeline.
Likelihood: Likely
Expected Size: 1 - 1
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: Possible
Expected Size: 1 - 1