Avalanche Forecast

Low - Uncertainty is due to the timing or intensity of solar radiation and its effect on the snowpack.

An above freezing layer will keep alpine temperatures warm and valley temperatures cooler in the Northern part of the region. In the South, the warm air will invade all elevations.

Friday: A mix of sun and cloud. Alpine temperatures near +6 and ridgetop wind strong from the southwest. Freezing levels near 3200 m on the Coquihalla and 1400 m in the North.

Saturday: Sunny. Alpine high of + 6 degrees. Ridgetop wind 25-45 km/hr in the North and 20 km/hr in the South. Freezing levels near 3200 m in the South and 2900 m in the North.

Sunday: Cloudy with light precipitation. Alpine temperatures near 0 and freezing levels falling to 2500 m. 

No new avalanche observations submitted on Thursday.

On Wednesday, the northern part of the region, several natural avalanches were reported up to size 2 with some older ones from the previous storm up to size 2.5. A couple of isolated natural glide crack avalanches up to size 1.5 were also reported. In the southern half, numerous natural wet loose avalanches occurred up to size 2 mostly from southerly aspects.

On Tuesday, a large size 3 natural avalanche was observed on a NE aspect at 2400 m. It was reported as a cornice failure triggering the slope below and appeared to have slid on the early November crust near the base of the snowpack.

As warm air and sunshine hit the region again Friday and Saturday I expect natural avalanche activity to occur. The longer the heat sticks around the deeper it drives into the snowpack potentially initiating larger avalanches. 

Have you been out and about in the mountains? If so please submit to the Mountain Information Network (MIN). It doesn't have to be technical it can be as simple as a photo. Photos are especially helpful! Sending out a big thank you to the already submitted MIN's this season. Thanks everyone!

Recent sun and warm air well into the alpine had the greatest impact on the upper snowpack, showing signs of instability and promoting further slab development and cohesion. This may be most concerning where these slabs sit above an old thin crust on south aspects and feathery surface hoar crystals in wind-sheltered areas. New surface hoar formation can be found on slopes where it was protected from the warm temperatures, sunshine and wind. Northerly aspects will likely see fresh wind slab development at upper elevations on leeward slopes and melt-freeze conditions may exist on most aspects and elevations.

The lower snowpack is characterized by a few crusts formed during warm periods over the last month. 

• In the north, treeline snowpack depth sits around 80 to 120 cm. The crust of note here is sitting near the base of the snowpack, likely surrounded by a weak layer of sugary facets. Snowpack tests and recent avalanche activity suggest that this layer could be triggered by humans and produce large avalanches.
• In the south of the region, the snow line has been reported around 700 m near Hope, and treeline snowpack depth sits around 80-150 cm. Melt-freeze snow surfaces likely exist after the rapid warming on Wednesday. The deeper crusts in this area are generally down around 60-80 cm in the alpine and well bonded to surrounding snow.

• Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
• Avoid steep slopes when air temperatures are warm, or solar radiation is strong.
• The likelihood of deep persistent slab avalanches will increase with each day of warm weather.