Avalanche Forecast
Regions: Olympics.
There may be some shallow storm and wind slab above treeline Sunday. Any new snow that does fall will be susceptible to sunbreaks later Sunday afternoon, so use extra caution on steeper solar slopes near and above treeline.
Detailed Forecast
A frontal system will bring renewed light rain and snow to the Olympics Sunday followed by showers Sunday afternoon. Increasing southerly ridge top winds may build new wind slabs on lee slopes, mainly northerly facing near and above treeline.Â
Any new snow that does fall will be susceptible to sunbreaks later Sunday afternoon, so use extra caution on steeper solar slopes above treeline.Â
Due to the low snowpack, especially below treeline, watch for terrain hazards such as open creeks, partially covered rocks and vegetation. Many areas below treeline do not have enough snow to cause an avalanche danger.
Snowpack Discussion
Last Sunday winter returned with a welcome 16-18 inches of new snow at the NWAC Hurricane Ridge station. A frontal boundary stalled over southern British Columbia brought occasional light rainfall to Hurricane Ridge on Thursday and Friday with the snowline likely extending above 6000 feet. Rainfall and mild temperatures late in the week helped stabilize and consolidate the briefly resurgent snowpack. However, webcams at Hurricane Ridge Friday and Saturday show the effects of the warming and rain this week with bare patches returning.
A few inches of new snow Friday and Saturday along with moderate winds may have built some small cornices along ridges and transported snow to build some small wind slabs on lee slopes.  Â
Avalanche Problems
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.
Aspects: South East, South, South West, West.
Elevations: Alpine, Treeline.
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, North West.
Elevations: Alpine, Treeline.
Likelihood: Possible
Expected Size: 1 - 1