Avalanche Forecast
Regions: Olympics.
Sunday may continue to be a tricky day to manage avalanche concerns. Winter like wind and storm slab should prevail at higher elevations with wet loose concerns at lower elevations. Heavier showers and strong spring solar effects can quickly change the snow conditions so pay close attention to weather through the day.
Detailed Forecast
Light occasional moderate showers should be seen on Sunday in the Olympics with fairly cool temperatures.
Watch for areas of wind slab from the previous couple days lingering on lee slopes. This is most likely on north to east slopes near and above treeline. Watch for signs of cracking or firmer wind transported snow and approach open lee slopes with caution.
New or new storm slab may not have stabilized yet on Sunday. This will also be likely on sheltered slopes where there was heavy snowfall or graupel which may have formed temporary weaker storm layers also near and above treeline.
Despite the mostly cloudy weather and cool temperatures on Sunday wet loose avalanche conditions are likely mainly on solar slopes near and below treeline. Watch for wet surface snow deeper than a few inches, roller balls in surface snow and small natural wet loose releases that usually precede more major wet loose snow avalanches. And remember brief sun breaks can quickly extend the wet loose concern to above treeline or to other aspects.  Avoid terrain traps where a small but powerful wet loose avalanche could have unintended consequences.
Snowpack Discussion
Fair weather was seen last weekend through Monday with Monday the warmest day. Reports from the Cascades during this period indicated some powder surviving on north slopes and wet loose avalanches on solar slopes. A crust should have formed on most solar slopes.
The weather pattern got activated again over the Northwest starting Tuesday. There has been about 1.5 feet of snowfall in the 4 days ending today at the NWAC station at Hurricane Ridge. There will have been less snowfall and rain at lower elevations. So it is getting to be a mix of winter like conditions at higher elevations and spring like conditions on solar slopes and at lower elevations.
A frontal system passing through on Friday brought moderate south winds and wet snowfall at Hurricane Ridge, with rain likely not far below in elevation. NWAC observer Katy Reid at Hurricane on Friday reported local wind slab along along lee ridges with pit tests giving stubborn but clean shears. She also found some storm snow instabilities giving clean results in hand tests at about 15 cm or 6" below the surface.
Hand pit results at Hurricane Ridge on Friday 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.
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: Alpine, Treeline.
Likelihood: Likely
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: Treeline, Below Treeline.
Likelihood: Likely
Expected Size: 1 - 1