Avalanche Forecast

Good

A series of frontal systems will send waves of moderate- heavy precipitation accompanied by strong to extreme winds through the forecast period. Model runs are in agreement with timing and precipitation amounts. Snow amounts indicated below represent the Southern part of the region (Coquihalla) while lower amounts are forecast for the Northern parts of the region.Saturday night: Snow amounts 20-25 cm. Ridgetop winds blowing moderate from the SW gusting to extreme values. Sunday: Snow amounts 20 cm. Alpine temperatures near -4.0. Strong-extreme SW ridgetop winds and freezing levels 900 m..Monday: Snow amounts 20 cm. Alpine temperatures near -6.0. Ridgetop winds light gusting strong from the South. Tuesday: Snow amounts near 10 cm accompanied by light ridgetop winds.

No new avalanche observations reported. With more snow and strong-extreme winds forecast, the size and destructive potential of the building storm slab will increase and avalanche danger will be high.

The Northern parts of the region have recently received up to 70 cm of new storm snow and the Southern areas have seen anywhere up to 120 cm. This new storm snow overlies a variety of old surfaces consisting of surface facets, surface hoar (more predominant at treeline and below treeline elevations), a scoured crust, wind press, or any combination of these. Professionals are expressing particular concern for the combination of buried facets on a crust being unusually reactive at lower elevations. Reports of whumphing and widespread avalanche activity further indicate a poor bond between the new snow and these old surfaces. Strong to extreme winds are shifting the new snow into deeper, reactive wind slabs in exposed terrain.The mid and lower snowpack are generally strong and well-settled. Although basal facets and depth hoar are likely to exist in the north of the region, but triggering has become unlikely.