Regions
Northwest Coastal.
Rising temperatures and sunny skies on Sunday will likely trigger loose wet avalanches on steep slopes facing the sun.
Confidence
Moderate - Due to the number of field observations
Weather Forecast
SUNDAY: Mostly sunny. Light northeasterly ridgetop winds. Alpine temperature +2. Freezing level rising to around 1400 m.MONDAY: Mostly sunny. Light northeasterly ridgetop winds. Alpine temperature 0. Freezing level around 1200 m.TUESDAY: Mostly cloudy with sunny breaks. Light southwesterly ridgetop winds. Alpine temperature -1. Freezing level around 1100 m.
Avalanche Summary
No new avalanches were reported in this region on Friday. On Wednesday, a size 2.5 persistent slab avalanche was remotely triggered by a group of skiers on a ridgetop from 10 m away. The avalanche failed on surface hoar about 70 cm deep on a north aspect at 1800 m. A size 2 wet slab was triggered by day-time warming in the same area near Bear Pass.
Snowpack Summary
10-20 cm of recent storm snow and strong variable winds have formed wind slabs on a variety of aspects at treeline and above.In the south of the region, two layers of surface hoar are buried approximately 70-100 cm deep. The layers are most prominent on north to east aspects and were buried early-March and mid-March. In the north of the region, these layers are around 40 cm deep.Bellow these March layers the mid-pack is generally well-settled and strong. However, shallower parts of the region, such as the far north, have weak sugary facets near the bottom of the snowpack.
Problems
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.
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.