Avalanche Forecast

A ridge of High pressure will bring cool and mostly clear conditions for the next few days. A storm on Sunday shoould track south of this region.

THURSDAY NIGHT: Cloudy with clear periods, light south wind, alpine low temperatures -9 C.

FRIDAY: Cloudy with sunny periods, light wind, high temperatures around -7 C.

SATURDAY: Mostly sunny, light to moderate south-west wind, high temperatures around -10 C.

SUNDAY: Cloudy with sunny periods and isolated flurries, moderate south winds, high temperatures around -6 C.

As the weather clears we are uncertain about how quickly the recent snow will gain strength and bond to old interfaces. Recent 15-40cm (more to the mountainous south) likely sits atop a weak layer of surface hoar in wind-sheltered areas at treeline and at upper below treeline elevations (above the extent of the rain crust estimated at 1500m). Wind slabs likely linger in higher wind-affected terrain.

With little in terms of field observations, a cautious and conservative approach to terrain is needed. Be aware of these new avalanche problems by looking for signs of instability like shooting cracks and whumpfs. Furthermore, an avalanche triggered in the upper snowpack could cause a larger deep persistent slab avalanche.

Our eyes and ears in the mountains are limited this winter due to fewer professional observations. If you go out in the mountains, please share your observations on the Mountain Information Network (MIN).

The combination of warm storm earlier this week followed by cooler temperatures has reworked the snowpack. Heavy rain was reported up to 1500 m, so lower elevations will now have a thick surface crust or "dust on crust". 15-40 cm of snow fell at higher elevations, with the largest accumulations around Valemount and Blue River.  

The most concerning part of the snowpack remains how well this new 15-40 cm of snow is bonding to a widespread buried surface hoar layer (or above sun crusts). Carefully assess steep open slopes at intermediate elevations if you see recent accumulations of dry snow (just above, at and below tree line). In other words - that zone of lower alpine terrain but above the rain line - could be holding the most dangerous problem: a storm slab over surface hoar or sun crust, especially where winds have helped create a slab.

In the alpine this snow has formed thick wind slabs, which should generally be strengthening quickly. As ever, assess how direct sun is affecting steep solar terrain.  

The most notable layer in the lower snowpack is a thick crust from November rains, which is sitting near the base of the snowpack, surrounded by a weak layer of sugary facets. It is most likely to be reactive to human triggers or from a step-down from a smaller avalanche in shallow, rocky areas in the alpine or on shallow steep solar faces.

• Investigate the bond of the recent snow before committing to your line.
• Approach steep open slopes at and below treeline cautiously, buried surface hoar may exist.
• Watch for signs of instability like whumpfing, hollow sounds, shooting cracks or recent avalanches.
• Be aware of the potential for large avalanches due to the presence of a deep persistent slab.