Avalanche Forecast

A clear period gives way to significant snowfall for Saturday at all elevations as freezing levels remain low. We'll see another shift in wind direction starting Sunday with the potential for the wind speed to be highest at lower elevations.

Thursday Night: Clear. No new snow expected. Light southwest wind. Treeline high around -13 °C, with a temperature inversion. Above 2000m temperatures will rise above -10 °vC.

Friday: Increasing cloud cover. Snowfall beginning late afternoon. Winds becoming moderate southwest. Treeline high around -14 °C.

Saturday: Overcast. 4-20 cm of snow expected overnight, and another 0-15 cm through the day. The higher amounts are forecasted for the south of the region. Moderate to strong southeast winds, trending to south at higher elevations. Treeline high around -12 °C.

Sunday: Mostly clear. No new snow expected. Moderate northeast winds, trending to strong at lower elevations. Treeline high around -12 °C.

Wind slabs formed on all aspects in exposed terrain are expected to remain sensitive to human triggers.

On Wednesday, one isolated size 2 avalanche was reported in the Skeena valley. It was reported as a glide slab failing on a smooth rock face.

The persistent slab problem appears to generally have stabilized in the south of the region but remains a concern in the north. We are now likely in a low probability/high consequence scenario with the persistent problem. 

On Tuesday, natural wind slabs to size 2 were reported in the north of the region. In the south, explosives were triggering wind slabs to size 2. This MIN report highlights the wind slab problem around Terrace. 

Given the variable nature of the recent wind, slabs should be expected on all aspects in exposed terrain. 

On Thursday, the wind shifted to the NW so new wind slab formation on south and east aspects is expected where there is still unconsolidated surface snow available for transport.

Over last weekend, the region typically saw 20-50 cm of new snow with the greatest amounts towards the SW of the region. This new snow was accompanied by strong SW winds which had formed reactive wind slabs in exposed terrain. On Monday and Tuesday, strong outflow (NE-E) winds formed wind slabs on South and West aspects.

The December 7 persistent weak layer is now typically down 40-70 cm except for near the immediate coast where it is closer to 100 cm. This interface may include a crust, facets, and/or surface hoar. This layer appears to be gaining strength through the south of the region but remains a concern for the north of the region. A bit deeper in the snowpack is the December 1 crust/facet layer which generally appears to have stabilized but may still be reactive in isolated areas. 

• Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
• Carefully assess open slopes and convex rolls where buried surface hoar may be preserved.
• Be aware of the potential for large avalanches due to the presence of buried weak layers.
• Recent wind has varied in direction so watch for wind slabs on all aspects.