Avalanche Forecast

A layer of surface hoar from mid-November buried 60-80 cm deep continues to be reactive. Widespread whumpfing and cracking continue to be reported.

On Friday, a remotely triggered natural avalanche was reported on a steep east-facing feature near Kootenay Pass, likely failing on this layer. Read the MIN report here. On Thursday, evidence of a natural cycle was observed to size 2 on north-facing terrain features around 2000 m.

Several other MIN reports from across the forecast region indicate the sensitivity of these layers, showcasing whupping, cracking, and reactive snowpack tests (MIN).

Thank you for all the great MIN reports! They are extremely helpful to us in the early season when snowpack information is limited. Keep them coming!

Cold temperatures and clear skies over the past few nights will promote surface hoar growth and faceting on the surface of the snowpack.

There are two prominent weak layers in the upper snowpack. A weak layer of surface hoar can be found 30-60 cm down. Another weak interface that was formed during the dry period in mid-November is buried 60-90 cm deep. This layer consists of sugary faceted grains, large surface hoar crystals in sheltered terrain features, and a crust on steep sun-exposed slopes. Reports of whumping, cracking, and recent avalanches suggest these interfaces are not bonding well.

We have limited information at this point in the season, we're hoping to gain more information on the distribution and sensitivity of these layers as we collect more field observations.

Snowpack depths average 80-160 cm in the alpine. Below treeline elevations are now above the threshold for avalanches in many areas.

Sunday night

Mainly clear, increasing high cloud in the morning. Westerly wind 10-25 km/h at ridgetop. Treeline temperature drops to a low of -18 C.

Monday

Mainly cloudy, light snowfall with trace accumulation. Westerly wind 10-35 km/h at ridgetop. Treeline temperature high of -9 C.

Cloudy with snowfall, up to 5 cm of accumulation expected. Westerly winds 15-40 km/h at ridgetop. Treeline temperatures reach a high of -10 C.

A mix of sun and cloud, light snowfall possible with trace accumulation. Westerly winds 10-30 km/h at ridgetop. Treeline temperatures reach a high of -9 C.

More details can be found in the Mountain Weather Forecast.

• Back off if you encounter whumpfing, hollow sounds, or shooting cracks.
• Remote triggering is a concern, watch out for adjacent and overhead slopes.
• Potential for wide propagation exists, fresh slabs may rest on surface hoar, facets and/or crust.