Avalanche Forecast
Regions: Olympics.
A cooling trend Wednesday night and Thursday should limit the loose wet problem to below treeline. Shallow new wind slab may build on lee slopes near and above treeline Thursday.
Detailed Forecast
An occluded front pushing through Wednesday night should be followed by light showers on Thursday and a cooling trend.Â
Shallow wind slab may build on lee slopes near and above treeline Thursday. Watch for new firmer wind transported snow mainly on lee N to SE slopes near ridges.Â
You should continue to watch for loose wet avalanche conditions below treeline Thursday especially on steeper slopes. Watch for wet surface snow deeper than a few inches that usually precede loose wet avalanches or other triggered or natural loose wet avalanches.Â
Snowpack Discussion
Weather and Snowpack
Dry weather with the warmest temperatures of the winter occurred February 7-10th with mild temperatures and high freezing levels.Â
A pair of warm fronts brought about 6 inches of new snow to Hurricane about Thursday to Saturday.
Rain and mild temperatures predominated Sunday and Monday with 1.5 inches of rain before a brief cooling trend brought a few inches of snow by Tuesday morning. Mild temperatures and windy conditions were seen on Wednesday.Â
Recent Observations
Professional NWAC observer Matt Schonwald was at Hurricane Ridge on Friday, Feb 12th. Recent warmth and persistent winds had generally created a dense and homogeneous snowpack without layers of concern. In the Hurricane Ridge area the snowdepth falls off rapidly below 4400 feet. Bare patches and/or thin snow cover are widespread along ridges and on south to west aspects. Matt and an NPS ranger did observe 2 glide avalanches that likely occurred the night of Feb 11th. The larger one, size D2.5, released in the 20th of June path down to a smooth shale bed. However, except in isolated terrain features, glide avalanches should not be a widespread concern in the Hurricane Ridge area.Â
No direct snowpack or avalanche observations have been received mid-week, but the snowpack is likely still homogenous with wet grains dominating the upper snowpack.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.
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