Avalanche Forecast

Thursday night: Increasing cloud. Strong to extreme south winds. Mild temperature inversion with warm air aloft, breaking down with the arrival of a cold front in the morning.

Friday: Cloudy with isolated flurries and a trace to 5 cm of new snow, easing overnight. Moderate southwest winds, easing overnight. Alpine high temperatures around -7 with freezing levels rising to 1100 metres.

Saturday: Cloudy. Light to moderate south winds. Alpine high temperatures around -7.

Sunday: Cloudy with scattered flurries continuing from the overnight period and 10-15 cm of new snow. Moderate to strong southwest winds. Alpine high temperatures around -7 with freezing levels rising to 1100 metres.

We're still light on field observations from the aftermath of Tuesday's storm, however it it's safe to assume it's been a busy couple of days for natural avalanches, with up to 40 cm of new snow blanketing the region and subsequently being redistributed by strong winds. Activity was likely less pronounced in the north of the region, which saw closer to 15 cm of new snow.

Observations from the neighbouring North Columbias may serve to illustrate the kind of activity that likely took place in southern parts of the region on Tuesday and Wednesday. Here, early observations show many storm and wind slab releases generally in the size 1.5-2.5 range with several reaching up to size 3. In the Trans-Canada corridor, a size 4 (VERY LARGE) avalanche ran on Mt. Laurie.

Persistent slab releases have not figured too prominently in reports thus far, but observations are still limited and the few that have been reported are notable. Check out this MIN from the Gorge area for an example of the isolated deep releases we're concerned about.

Looking forward to Friday, it remains a good idea to give newly formed wind slabs a wide berth as you approach wind affected terrain, and to remain suspicious of steeper sheltered slopes where new snow may have slabbed up over a layer of surface hoar or crust. Using small test slopes to investigate the bond of new snow is a good plan, but be cautious about extending your observations to more committing terrain.

Since field observations in this region are limited, please consider submitting your observations to the Mountain Information Network. 

15-40 cm of new snow fell in the region during Tuesday's storm, with accumulations greatly favouring the south of the region. This buried wind affected surfaces at upper elevations, as well as surface hoar in wind sheltered areas and a thin crust on solar aspects. 

The new snow will take time to form a bond with these previous surfaces, particularly in spots harbouring surface hoar or crust. In exposed areas, elevated winds have been redistributing new snow into reactive wind slabs and adding to cornices.

A couple of persistent weak layers exist in the upper to mid snowpack, down 20-60 cm and 70-100 cm. The distribution of these layers are variable, the upper layer spotty surface hoar at treeline and below and the lower layer may present as decomposing surface hoar and/or a crust. It has been reported as most prevalent in areas near Valemount. 

Avalanche activity on these layers has dwindled since the last storm and recent snowpack tests results have been increasingly resistant, but still showing some propagation. Given their age (particularly the deeper layer) and the testing load brought by Tuesday's storm, the outlook is good for these layers to finally become dormant as our current surface instabilities diminish.

• Continue to make conservative terrain choices while the storm snow settles and stabilizes.
• Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
• Use small low consequence slopes to test the bond of the new snow.