Avalanche Forecast

Fair - Intensity of incoming weather is uncertain

Tuesday: A significant storm is expected to hit the region starting Tuesday around noon and ramping up during the afternoon and overnight. Expect up to 20 cm new snow by the end of the day and another 20-30 overnight. Models indicate the south of the region will see more snow than the north. Ridgetop winds gusting to 75 km/h from the southwest. Freezing level rising briefly to around 1500m late on Tuesday, but mostly staying around 800 m.Wednesday: Snowfall, heavy in the morning, easing through the day. Temperatures falling rapidly. Winds diminishing.Thursday: Dry and cold. Temperatures around -12C. Winds becoming light northerly.

A thin, but relatively wide-propagating avalanche was triggered on Needle Peak in the Coquihalla Mountains on Sunday. You can read the description here. This kind of avalanche is likely to increase in size and destructive potential with additional loading by new snow and wind.

New snow has fallen on old surfaces comprising surface hoar and facets. The crystals are better developed in shady areas, but on solar aspects they lie on top of a sun crust. On all aspects, the bond between the old snow and the new storm snow is likely to be poor. In exposed areas, particularly on northerly aspects, wind slabs have formed and are reported to be easily triggered by light loads such as skiers. Below the recent storm snow, and through most of the middle portion of the snowpack, no significant weak layers have been reported. Near the base of the snowpack, a crust/facet layer exists, which is now unlikely to be triggered, except perhaps by heavy triggers in steep, shallow, rocky terrain where more faceting has taken place.