Avalanche Forecast
Regions: Olympics.
Watch for small areas of firmer, wind-transported snow on isolated, lee terrain features. Watch for loose-wet snow avalanches releasing from sun exposed rock faces or below cliffs or rock bands.
Detailed Forecast
Continued sunny and mild weather is expected Wednesday with some moderate easterly winds near ridges.
Recent snow layers will continue to stabilize in the Hurricane Ridge area.Â
Small wind slabs may form on a variety of aspects, mainly on exposed lee slopes receiving any transported snow. These wind slabs are expected to be stubborn or difficult to trigger. Watch for small areas of firmer, wind-transported snow on isolated, lee terrain features.
Continue to watch for isolated, small, loose wet avalanches on steep sun exposed terrain during the late morning or afternoon, especially on unsupported slopes or near rocks.
Early season terrain hazards still exist, such as poorly covered rocks, vegetation and creeks, particularly at lower elevations.
Snowpack Discussion
Warm, very wet weather before Thanksgiving caused wet snow and glide avalanches as well as snowpack consolidation, leaving a strong crust as a gift. There are no snowpack concerns below the Thanksgiving crust and in general new snow received post-Thanksgiving has reportedly bonded well.
A series of frontal systems produced snow over the week following the Thanksgiving warm period: Hurricane Ridge received about 2 feet of snow.
This includes the most recent snow of about 10 inches received at Hurricane Ridge ending Sunday morning, December 3.
Increasingly fair weather Sunday through Tuesday has allowed for a slow decrease in danger with about 2-4 inches of snowpack settlement noted at the Hurricane weather station.
Observations
No observations have been received since Sunday.
Friday morning: NPS rangers reported 5" of new snow along with active wind transport of the new snow.Â
Saturday morning: NPS rangers report 7" of new snow. Small, 15 cm deep natural storm slab avalanches were being triggered by tree bombs along the road. Snow pit tests on a north slope at 5200' gave ECTP2 and ECTP4 @ 10 and 15 cm, respectively. Clean propagation was observed in both cases. On this test slope, the pencil hard Thanksgiving rain crust was down 55 cm.
On Sunday morning, the Hurricane Ridge rangers report small, loose dry avalanches along the road with no slab character. Ski penetration was 6" with generally right-side-up near surface snow.
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: 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: Treeline, Below Treeline.
Likelihood: Possible
Expected Size: 1 - 1