Avalanche Forecast

Moderate - Forecast snowfall amounts are uncertain. Uncertainty is due to the timing of the incoming weather system.

Wednesday: Snow accumulating through the day 10-15 cm. Alpine temperatures near -4 and ridgetop wind strong from the southwest. Freezing levels 400 m.

Thursday: Mix of sun and cloud with snow up to 5 cm. Alpine temperatures near -5 and freezing levels 900 m. Ridgetop wind strong from the West.

Friday: Mix of sun and cloud. Alpine temperatures near -6 and freezing levels in the valley bottom. Ridgetop wind strong from the northwest.

 

No new natural avalanche activity was observed Tuesday. On Monday, explosive triggered loose dry avalanches up to size 2 were reported from steep below treeline terrain. Additionally, some older (past 24-48hr) natural glide slab releases up to size 2 were spotted. In the far southern part of the region on Mt. Alexandra, an old (past 72hr) natural deep persistent avalanche release was reported size 3 from a NE aspect at 1700 m. 

With strong wind and new snow forecast for later Wednesday and Thursday, I suspect new wind slabs and storm slabs will be touchy. Especially where they sit above surface hoar, crust, or old surface facets. 

Up to 10 cm of recent snow fell by Tuesday bringing 25-55 cm of accumulative storm snow from the past week over a variety of older snow surfaces. These old surfaces, at upper elevations (upper treeline and the alpine), include surface hoar in locations sheltered from the wind, surface facets, and stiff wind affected snow. At lower elevations (lower treeline and below treeline) 10-20 cm of snow sits above isolated pockets of surface hoar and a crust that is more predominant on solar aspects. Strong winds have stiffened the surface snow and have formed reactive wind slabs, especially in areas where they sit above the buried surface hoar. This recent MIN report is a great example of that. With forecast snow and wind Wednesday/ Thursday I suspect more reactivity will occur.

The layers in the mid and base of the snowpack have gained strength with high snowfall amounts in January. Deep persistent layers appear to have mostly gone inactive with the exception of the Bear Pass area and the far reaches south of Kitimat that have seen some sporadic avalanche activity on weak snow near the base of the snowpack and triggered by large loads such as explosives, icefalls or cornice collapses.

• Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
• Watch for signs of instability like whumpfing, hollow sounds, shooting cracks or recent avalanches.
• Carefully assess open slopes and convex rolls where buried surface hoar may be preserved.
• Watch your sluff: it may run faster and further than you expect.