Avalanche Forecast
Regions: Olympics.
The overall snowpack is strong and well consolidated after more than a week of mild, dry weather. Watch for shallow wet surface snow conditions on some steep sun exposed slopes, especially below rocks or cliffs and above terrain traps where even small slides could be dangerous. Low snow cover hazards may present a greater concern than the avalanche hazard.
Detailed Forecast
Slightly cooler conditions are expected on Tuesday, but the freezing levels are still very high for December. Winds will be generally light SSW.
In the Hurricane Ridge area, temperatures reached the upper-50's Monday.
Surface melt-freeze crusts are continuing to form overnight on solar exposed slopes and softening through the day. Loose wet avalanches are unlikely, but might be encountered in isolated steep solar exposed slopes below rocks or trees absorbing more radiation. Â
The nice riding and skiing conditions found Sunday are likely to still be found on north-facing terrain Tuesday as little change in the snowpack structure is expected.Â
Early season terrain hazards still exist, such as poorly covered rocks, vegetation and creeks, particularly at lower elevations, and on exposed ridges where wind events have stripped much of the seasons snowcover.
Snowpack Discussion
Strong high pressure has now been over the region for over a full week. Sunshine and very mild temperatures have been the story with cooler temperatures and areas of low clouds at lower elevations. This weather has allowed for overall strengthening and consolidation of an already strong snowpack. The snowpack is well consolidated with settled old storm snow of about 1 to 1.5 feet over the strong Thanksgiving rain crust.Â
No human-triggered avalanches have been reported in over a week. Some natural small loose wet slides have occurred on mainly steep sun exposed slopes over the last week, but have become much less frequent over the past several days. Active wind loading has not been observed since late last week. See the Mt. Baker zone/observation for local glide avalanche concerns in that zone.Â
Surface conditions are highly variable. On solar aspects, surface melt-freeze crusts reform every night. On shaded and sheltered aspects, settled storm snow is still providing some nice skiing and riding conditions. Many aspects in higher terrain now feature wind stiffened snow. Near surface faceting and surface hoar growth has been reported on colder, non-solar aspects throughout the Cascades but especially in the cooler Cascade Passes. These persistent grain types will become important when snowfall returns and watched as potential future weak layers.Â
Observations
NWAC Professional Observer Matt Schonwald was in the Hurricane Ridge area on Sunday, December 10th. The average height of snow in most areas was consistently around 4 feet deep. About 16 inches of settled and creamy snow was found well bonded to the Thanksgiving rain crust with strong snow to the ground.
Terrain up to 45 degrees was skied with no signs of instability. Only a few isolated loose wet slides were evident from the past day or so and were small and isolated to steep slopes above terrain absorbing greater radiation, such as cliff and rock band features.
There was some small surface hoar growth on sheltered E-SE facing slopes, not receiving direct low angled sun. No surface hoar or near surface faceting was seen on other slopes, including north facing.
The Hurricane rangers on Friday and Saturday reported few small pinwheels on solar road cuts from the past couple days, no avalanches, with settled powder lingering on north and east slopes.
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.
Elevations: All elevations.
Likelihood: Unlikely
Expected Size: 1 - 1