Regions
Northwest Coastal.
Confidence
Fair - Timing, track, or intensity of incoming weather is uncertain for the entire period
Weather Forecast
Saturday: Cloudy with scattered light precipitation possible. Light to moderate southerly winds. Freezing level around 1500 m.Sunday: Mainly dry and sunny. Freezing level around 1200 m, falling to near valley floor overnight. Light winds.Monday: Light, scattered precipitation. Freezing level rising to around 1000 m in the afternoon. Light winds.
Avalanche Summary
Reports of natural glide activity from the Skeena corridor continue. Cornice fall and ice fall triggered 1-1.5 m deep wet slabs in the Bear Pass area on Thursday.
Snowpack Summary
New wind slabs may have built on lee slopes. The snow surface below about 1000 m has not been re-freezing overnight, leading to weak soft snow. Large cornices and ice cliffs pose a threat from above.As we transition into spring, the surface layers have a great deal of influence on the snowpack. When there is a solid re-frozen surface crust, travel is fast and easy, and the snowpack is held together by the surface cap. Any deeper persistent weak layers are unlikely to fail until the surface cap breaks down from daytime heating. When there is no crust, surface layers and any deeper weak layers may fail, depending on the amount of heat and the triggering force that is applied. If it cools off and snows, new snow and wind slabs may not bond well to the hard spring crusts. For more information on Spring Conditions and ways to mitigate risk, please visit the new Forecasters' Blog Post.
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.
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.
Wet Slabs
Wet Slab avalanches are the release of a cohesive layer of snow (a slab) that is generally moist or wet when the flow of liquid water weakens the bond between the slab and the surface below (snow or ground). They often occur during prolonged warming events and/or rain-on-snow events. Wet Slabs can be very unpredictable and destructive.