Avalanche Forecast

Saturday night: Cloudy with increasing snowfall bringing 10-20 cm of new snow. Strong to extreme southwest winds.

Sunday: Cloudy with continuing snowfall bringing an uncertain 10-25 cm of new snow, easing overnight. Extreme southwest winds easing over the day. Alpine high temperatures around -6.

Monday: Cloudy with scattered flurries and about 5 more cm of new snow, increasing overnight. Light to moderate southwest winds, increasing and shifting south over the day and overnight. Alpine high temperatures around -5.

Tuesday: Cloudy with continuing snowfall bringing 15-30 cm of new snow, closer to 25-40 cm with overnight amounts. Strong south winds. Alpine high temperatures around -3.

Observations from the last couple of stormy days are still limited, however a MIN report from Thursday in the Shames area paints a clear picture of recent slab reactivity in specific wind loaded features. These touchy conditions should ramp up a couple of notches for Sunday as heavy snowfall and high winds set up a widespread new storm slab problem

A natural wind slab avalanche cycle with numerous wind slabs from size 2 to 3.5 (large to very large) was reportedly ongoing in the Bear Pass area on Wednesday morning and again on Friday morning. Natural wet loose and glide avalanches have accompanied this activity below about 900 metres. This activity was quite a bit more pronounced than what was reported from the Shames area and the Skeena corridor during the same period.

30-40 cm of new snow is expected to accumulate in the region over Saturday night and Sunday. Overnight snowfall will be accompanied by strong to extreme south winds.

The new snow will add to wind affected recent snow in exposed areas and settled storm snow in sheltered areas. It will add significant load to a couple of deeply buried weak layers that haven't yet been ruled out as problems, especially given forecast loading. 

The first and most concerning is a roughly 70-100 cm-deep persistent weak layer of surface hoar buried March 12 on sheltered northerly aspects around treeline. Deeper down, around 100 to 300 cm now overlies another layer of surface hoar (and faceted snow) buried in mid-February that may still be a concern in shallower snowpack areas. Although they haven't produced recent avalanches, professionals in the region have been tracking and treating these layers with caution. Loading from the storm could well result in some step-down activity to produce very large and destructive avalanches.

The mid and lower snowpack is well settled and strong in most areas.

• Use increased caution at all elevations. Storm snow is forming touchy slabs.
• Use conservative route selection. Choose simple, low-angle, well-supported terrain with no overhead hazard.
• Storm slab size and sensitivity to triggering will likely increase through the day.