Avalanche Forecast

WEDNESDAY NIGHT: Partly cloudy. 0-5 cm of snow expected. Moderate to strong southwest ridgetop winds, trending to extreme in the high alpine. Freezing level dropping to around 750 m. Alpine low around -6 °C. 

THURSDAY: Partly cloudy. 0-5 cm of snow expected. Moderate to strong southwest ridgetop winds. Freezing level rising to around 1000 m. Alpine high around -4 °C.

FRIDAY: Partly cloudy with scattered flurries. Moderate to strong south ridgetop winds, periods of extreme southwest in the high alpine. Freezing level at valley bottom in the morning, rising to around 1000 m in the afternoon.  

SATURDAY: Mostly sunny with scattered flurries. Moderate southwest ridgetop winds. Freezing level at valley bottom in the morning, rising to around 750 m in the afternoon.  

No new avalanches were reported on Wednesday before 4 pm. 

On Tuesday, natural windslab avalanches up to size 2 were reported, as moderate winds continued to move snow. 

A couple of notables:

-Northwest of Hazelton, a rider triggered slab avalanche was reported on a north aspect around treeline. It started on the mid-March surface hoar layer, and it stepped down to the mid-February surface hoar layer. 

-Northeast of Hazelton, a size 2 windslab avalanche was reported that was triggered by a natural cornice failure. It was on a northeast facing slope in the alpine.  

On Monday, north of Smithers, a naturally triggered size 1.5 windslab avalanche was reported on a steep, northeast facing, treeline feature.

The late February surface hoar has shown reactivity in recent snowpack tests, and avalanche activity in the last week. A remote size 1.5 was triggered on a northeast aspect at 1450 m. A MIN report describes a size 2 slab avalanche triggered by a snowmobile on a southeast facing alpine slope from Saturday. This layer is most likely to be triggered where winds are loading sheltered open slopes at treeline. 

15-25 cm of storm snow is being redistributed into wind loaded pockets by moderate to strong southwest winds. This overlies a sun crust on solar aspects, and a temperature crust on all aspects as high as 1700 m. Some operations have reported surface hoar in this layer on sheltered north aspects. Those specific locations could be of more concern as windslabs continue to build.  

Around 30-45 cm deep, a surface hoar layer buried in late February is preserved in wind sheltered features at treeline and low alpine elevations. On sun affected aspects, this interface exists as a crust. This layer has shown to be reactive in snowpack tests and recent avalanche observations. 

The thick mid-February crust is now buried 50-80 cm deep, and in terrain where it is topped by a layer of loose, sugary facets, it could be possible to trigger with very large loads such as avalanches in motion or cornice falls.

The lower snowpack is well protected by the mid-February crust, and triggering avalanches below this layer is unlikely at this time. 

• Be careful with wind loaded pockets, especially near ridge crests and roll-overs.
• Wind slabs are most reactive during their formation.
• Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
• If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.