Regions
Northwest Coastal.
Confidence
Fair - Due to variable weather conditions
Weather Forecast
A series of Pacific frontal waves and upper troughs will bring continued unsettled weather through the forecast period. Light -moderate precipitation amounts can be expected daily. With fast moving systems, timing seems to be hard to pinpoint. A strong upper SW flow will provide warmer the normal temperatures, rising freezing levels in the afternoon, then falling during the night. Things should start to cool off significantly by Friday. Wednesday: Snow amounts 5-10 cm above 1100 m. Ridgetop winds moderate from the South. Freezing levels 1000-1500 m. Thursday/Friday: Moderate precipitation on Thursday, light-moderate for Friday. Ridgetop winds mod-strong from the SW. Freezing levels 1000 m, falling to 500 m.
Avalanche Summary
Most operations have reported very little avalanche activity within their tenures. Reports of glide cracks continue to widen on solar aspects. On Sunday natural cornice failures triggered slab avalanches up to size 2.5 on the slopes below. Unsettled weather conditions are forecast. It's important to pay attention to weather, and it's influence on the snowpack when recreating in your local mountains. I suspect the period will be fairly cloudy, but if periods of sun shine through, beware of solar aspects.
Snowpack Summary
Moderate to strong southeast winds have created wind slabs on opposite slopes and terrain features in the alpine, and treeline. Spring-like conditions have existed over the past several days. This has formed crusts on solar aspects at all elevations that become moist under sunny skies during the day. Melt-freeze conditions exist on all aspects below 1000 m. This has developed a well settled upper snowpack with no significant layers of concern. New surface hoar growth up to 10 mm has been reported on sheltered North aspects. Forecast snow may initially have a poor bond to these new surface forms (crusts, surface hoar). Below all this, down 60-120 cm exists a spotty surface hoar/ facet interface. Operations from the field noted no recent activity on this layer. I suspect it's becoming dormant, but would be suspicious of large triggers like cornice fall, or under the weight of a sled and it's rider in specific areas. Cornices in the region are reported to be very large and potentially unstable.
Problems
Wind Slabs
Wind Slab avalanches are the 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.
Cornices
Cornice Fall is the release of an overhanging mass of snow that forms as the wind moves snow over a sharp terrain feature, such as a ridge, and deposits snow on the downwind (leeward) side. Cornices range in size from small wind drifts of soft snow to large overhangs of hard snow that are 30 feet (10 meters) or taller. They can break off the terrain suddenly and pull back onto the ridge top and catch people by surprise even on the flat ground above the slope. Even small cornices can have enough mass to be destructive and deadly. Cornice Fall can entrain loose surface snow or trigger slab avalanches.
Loose Wet
Loose Wet avalanches are the 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. 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.