Avalanche Forecast
Regions: Olympics.
Watch for new and older wind slab on lee aspects near and above treeline. Wet loose avalanches should be confined to lower elevations. Be prepared if weather and avalanche conditions deteriorate quicker than forecast on Thursday.
Detailed Forecast
Rain and snow at relatively cool snow levels should increase in the afternoon Thursday, potentially causing wet loose concerns below 4000 ft and building generally shallow wind slab on NW thru E aspects near and above treeline. Â
Beside building new wind slab, older wind slab may locally still be sensitive near and above treeline formed over the weekend.  Watch for signs of cracking or firmer wind transported snow and approach open lee slopes with caution.
Remember to watch for cornices if you venture onto ridges and avoid slopes below cornices. Cornice failures are often seen during the transition to spring weather. Cornices have grown large recently and often break back much further than anticipated.Â
Snowpack Discussion
March ended with a return to winter; a storm cycle that began last week peaked over the weekend and delivered about 2 ft of snow at the Hurricane Ridge NWAC weather station. Â
Increasing rain and snow, winds and warming temps began the increase in avalanche activity Friday with sensitive wind slab reported in the afternoon. Natural wind slab avalanches likely from Saturday were found at Hurricane by Katy on Sunday with several releases up to size 2, mainly 6-12 inches, but with one slab stepping down 2.5 ft on a north slope. Tests indicated a clean interface at about 20 cm in the storm snow. By later Sunday, additional new snow at slightly colder temperatures was creating additional storm and wind slab concerns, especially with the effects of strong solar input at times.
Little or no new snow has fallen since Sunday with periods of sunshine and temperatures reaching in the low 40's midweek. This should have allowed storm weaknesses to quickly settle and stabilize.  While we have been in a stabilizing pattern there still may be pockets of unstable wind slab near and above treeline.   Â
The Park ranger at Hurricane Tuesday morning reported widespread but shallow loose wet slides that released during warming Monday.
Wind slab cracking from ski at Hurricane Ridge, near treeline, Sunday 3/30Â by NWAC observer Katy Reid.
Natural wind slab avalanches found at Hurricane on Sunday 3/30 by NWAC observer Katy Reid.
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: Possible
Expected Size: 1 - 1
Loose Wet
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.
Elevations: Below Treeline.
Likelihood: Possible
Expected Size: 1 - 1