New snow and wind are creating deeper and increasingly destructive storm slabs ripe for human triggering. Sticking to simple terrain would be a great way to manage the elevated hazard on Wednesday.
Confidence
Moderate - Timing, track, or intensity of incoming weather system is uncertain
Weather Forecast
Tuesday Night: 15-25cm of new snow / Moderate to strong southwesterly ridgetop winds / Freezing level rising to around 1400m.Wednesday: 5-10 cm of new snow / Moderate southwesterly ridgetop winds / Freezing level around 1000m.Wednesday night: 20-30 cm of new snow / Strong southerly ridgetop winds / Freezing level around 800m.Thursday: 20-30 cm of new snow / Strong southerly ridgetop winds / Freezing level around 800m.Friday: 15-20cm of new snow / Light to moderate southwesterly ridgetop winds / Freezing level around 500m.
Avalanche Summary
On Tuesday, a size 1.5 skier triggered storm slab avalanche was reported near Mt. Seymour. With more snow and wind on the way, natural and human-triggered storm slab activity should continue throughout the week.
Snowpack Summary
In recent days the region was pummeled by heavy precipitation with the rain line hovering around 800m. As of Tuesday morning, the 72 hour precipitation totals were up to 130mm on the North Shore mountains with closer to 60mm falling north of the Fraser Valley. Strong to extreme winds have redistributed the new snow into deep, dense and potentially destructive storm slabs while rain has saturated the snowpack at lower elevations. The reactivity of the new storm slabs is likely to vary greatly depending on elevation/ temperature and orientation to wind. In general, I would expect the touchiest conditions to exist in exposed, higher elevation terrain.
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.