Avalanche Forecast
Regions: Olympics.
The avalanche danger should decrease further on Monday. E-SE winds may distribute shallow amounts of recent snow onto westerly aspects above treeline. Increasing clouds should lower the likelihood of small loose wet slides.
Detailed Forecast
Increasing cloud cover should quickly spread from south to north over the Cascades and Olympics on Monday. Precipitation may develop for the southern Washington Cascades Monday afternoon but hold off until the evening for the Olympics.Â
The avalanche danger should decrease further on Monday. Light to locally moderate E-SE winds may distribute shallow amounts of recent snow onto westerly aspects above treeline. Older wind slab may linger on NW to SE aspects. Watch for firmer wind transported snow on all aspects, especially in areas of complex terrain.Â
Increasing clouds should lower the likelihood of small loose wet slides Monday. If solar radiation is more intense than forecast, expect the likelihood for natural and human triggered loose wet avalanches to increase on steeper solar slopes. Watch for surface wet snow deeper than a few inches, rollerballs or increasing small natural releases. Avoid areas with terrain traps where a small loose wet avalanche could have unintended consequences.Â
It is always a good plan to travel well back from ridges, suspected of cornice formation, or on steep slopes below cornices.
Snowpack Discussion
Weather and SnowpackÂ
The first week or so of March was very cool and snowy. NWAC stations along the west slopes of the Cascades and Olympics piled up about 3 to 8 ft of snow with the most at Mt Baker.
The 2nd week of March was equally active with non-stop Pacific frontal systems pummeling the PNW. Unfortunately these systems delivered far more rain than snow. At least two regional avalanche cycles occurred during the stretch including a very active avalanche cycle in the Hurricane Ridge area 3/9 through 3/10 with large or very large natural and human-triggered avalanches reported. Significant snowpack consolidation occurred over this period due to rainfall and warmer temperatures.Â
After a short respite from the active weather pattern on Thursday, another strong low pressure system brought several inches of rain to the west slopes of the Cascades and Olympics. Several inches of snow accumulated early Friday night before continued warming pushed snow levels above Hurricane Ridge with moderate rain seen through early Saturday morning. Rapid cooling later Saturday morning was followed by generally light snow showers with little in the way of new snow accumulation. Sunday was cool with light winds and mostly sunny skies.
Recent Observations
NPS rangers at Hurricane Ridge reported about 5 inches of wet snow Saturday morning with little sign of recent wind transported snow.  A public observation from the Obstruction Point Road noted ongoing wind transport, a supportable rain crust and lingering giant cornices along N-NE aspects of ridge-lines Saturday.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.
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.
Aspects: South East, South, South West, West.
Elevations: All elevations.
Likelihood: Possible
Expected Size: 1 - 1