Watch out for slopes being warmed by direct sun. This may locally raise the avalanche danger.
Confidence
Fair - Due to limited field observations
Weather Forecast
Monday: No snow. Mainly sunny. Light winds. Freezing level around 1200 m.Tuesday: Light snow. Light S winds. Freezing level around 1100 m.Wednesday: Light snow. Light S winds. Freezing level around 900 m.
Avalanche Summary
A widespread natural avalanche cycle (with avalanches from size 2-4) occurred on Friday/Saturday in response to intense storm-loading. Numerous large, deep fracture lines can be seen from the Sea-to-Sky corridor. These failed low in the start zone, leaving hangfire (unreleased areas of the slope). Numerous size 1-2 slabs were also triggered by skiers directly, remotely, and sympathetically at and below treeline. These failed on either storm slab weaknesses or buried persistent weak layers.
Snowpack Summary
Strong NW winds redistributed storm snow onto south and east aspects on Sunday. This reverse loading pattern may have left wind slabs in unexpected locations.The recent storm delivered well over 100 mm of precipitation, which fell with warming temperatures, dropping rain below about 1500-1900 m, depending on location. Strong southerly winds during the storm created wind slabs on lee terrain. Numerous weaknesses developed within the storm snow. A weakness of surface hoar and/or a crust exists within the upper snowpack (now 1-2 m deep), which has been reactive over the last week, creating very large avalanches. Direct sunshine may trigger some further shedding of storm snow on Monday. The lower snowpack is well settled.
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.
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.