Confidence
Fair - Forecast snowfall amounts are uncertain on Saturday
Weather Forecast
Synopsis: A weakening upper trough stalled off the southern BC coast should continue to deliver light snowfall Saturday night and scattered very light snowfall on Sunday. Look for gradual clearing on Monday.Saturday Night: Precipitation: 1 - 6mm | 2 - 10cm; Wind: Treeline: Light, SW | Ridgetop: Moderate, SWSunday: Freezing Level: 1100m - 1200m; Precipitation: 0-2mm | Trace; Wind: Treeline: Light, SW | Ridgetop: Light, SWMonday: Freezing Level: 1300 - 1600m; Precipitation: Nil; Wind: Treeline: Light, SW | Ridgetop: Light, WTuesday: Freezing Level: 1200 - 1700m Precipitation: Nil; Wind: Treeline: Light, Variable | Ridgetop: Light, NW
Avalanche Summary
Avalanche activity on Friday was limited to point releases out of north facing terrain at treeline which resulted in loose snow avalanches to size 1.
Snowpack Summary
On Friday night 10 - 25cm of new snow fell accompanied by strong southerly winds. There may be some areas where the recent snow does not bond well to melt-freeze crusts on solar aspects. The persistent weak layers from early March and early February continue to be a concern. The March weak layer of wind-scoured crusts, melt-freeze crusts, and/or surface hoar is reported to be down 60 - 100cm. The February crust/facet/surface hoar layer is now deeply buried down 150 - 250cm and may still be triggered by heavy loads like cornice falls or storm slab avalanches in motion. Long fracture propagations resulting in very large avalanches are possible with this layer. Avalanches releasing on these layers may step down to the ground during periods of strong solar radiation or warm spring rain.
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.
Deep Persistent Slabs
Deep Persistent Slab avalanches are the release of a thick cohesive layer of hard snow (a slab), when the bond breaks between the slab and an underlying persistent weak layer deep in the snowpack. The most common persistent weak layers involved in deep, persistent slabs are depth hoar or facets surrounding a deeply buried crust. Deep Persistent Slabs are typically hard to trigger, are very destructive and dangerous due to the large mass of snow involved, and can persist for months once developed. They are often triggered from areas where the snow is shallow and weak, and are particularly difficult to forecast for and manage.