Avalanche Forecast
Regions: Olympics.
Approach avalanche terrain especially near and above treeline with caution on Friday in the Hurricane Ridge area. Time and patience is advised to let recent storm snow instabilities heal. Recent and fresh wind slab, should exist near and above treeline on a variety of aspects.
Detailed Forecast
Snow levels should eventually settle around 4000-4500 feet Thursday night and Friday across the region. Light showers seen through Friday morning should taper down in the afternoon.Â
Approach avalanche terrain especially near and above treeline with caution on Friday in the Hurricane Ridge area. Time and patience is advised to let recent storm snow instabilities heal. Recent and fresh wind slab, should exist near and above treeline on a variety of aspects. Small loose wet avalanches are possible below treeline and could push you into a terrain trap.Â
Despite the recent snow, early season hazards still exist. Many creek beds have still not filled in for the winter.
Snowpack Discussion
12-14 inches (30-35 cm) of storm snow overlies the most recent rain crust in the Hurricane Ridge area in non-wind affected terrain. Below this rain crust, no notable layers of concern have been identified in the snowpack.Â
The height of snow across the terrain is quite variable with low snow in many areas below treeline. Even in areas near and above treeline, specific slopes have low snow cover where wind, rain and warm temperatures have stripped much of the season's snowfall. Numerous obstacles still exist at all elevations.Â
Observations
NWAC pro-observer Matt Schonwald was at Hurricane Ridge on Thursday 1/11. Matt found despite the significant storm snow still accumulating at day's end, the below treeline elevation band had quite variable snowcover. Around Hurricane Ridge at 5200', the east side of the ridge had a snowdepth of 2.5 feet and the west side had about 5 feet. Reactive storm layers were identified in snowpit tests, but signs of natural slab activity were not observed. Winds were actively transporting new snow near and especially above treeline, but the loading pattern was variable. Small loose wet avalanches were observed releasing in steep terrain above the road at about 4500' during gradual warming on Thursday.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: All aspects.
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
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