The wet, warm, and windy storm will result in High avalanche danger.
Confidence
Fair - Timing, track, or intensity of incoming weather system is uncertain
Weather Forecast
Warm, wet, and windy overnight as another 10-15 mm of precipitation moves into the region. The freezing level is expected to be about 2500 metres overnight and then rise up close to 3000 metres on Saturday. Another 5-7 mm during the day on Saturday with strong Southwest winds, and then another 3-5 mm by Sunday morning. On Sunday the freezing level may start to creep down a bit in the alpine, but still very warm in the valleys. Forecast precipitation for Sunday and Monday are starting to look a bit lower, with only 2-3 mm expected on Sunday and 1-3 mm for Monday. Freezing level should remain close to 2400 metres on both days.
Avalanche Summary
Several natural wind slab avalanches were reported during and at the end of the storm that ended early Monday. On Monday one natural size 3 avalanche and one size 1.5 accidentally triggered avalanche were reported from the South Chilcotin Mountains. These were both wind slabs on northerly aspects near ridge top. Numerous size 1-2 loose wet slides were observed in the Coquihalla on Tuesday.
Snowpack Summary
New storm snow is sitting on a sun crust or surface hoar that caps the 30-50 cm of settling storm snow or faceted powder. Deep and dense wind slabs are likely bonding poorly to another hard crust and/or surface hoar layer in exposed wind-affected terrain. The bond to the crust could be somewhat variable but many observers report a good bond. Where surface hoar is present (possibly above the crust) the storm slab has been more reactive to ski testing on steep unsupported features. Deeper snowpack weaknesses are still on our radar, but seem to be dormant for the time being.
Problems
Storm Slabs
Storm Slab avalanches are the release of a cohesive layer (a slab) of new snow that breaks within new snow or on the old snow surface. Storm-slabs typically last between a few hours and few days (following snowfall). Storm-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.