Avalanche Forecast

Starting the New Year with a Bang (of fresh snow)!

Saturday Overnight: The storm arrives in earnest. Strong to extreme southwest winds will accompany 20-40cm of new snow accumulation. Alpine temperatures rising to around -8 C.

Sunday: We are in the thick of it. Heavy snowfall upwards of 40 cm of new snow accumulation. Strong to extreme southwest winds with freezing levels potentially rising as high as 1000m. Continued snowfall overnight with another 10-30 cm of accumulation. 

Monday: And it continues! Winds easing into the moderate range from the southwest, another 5-15 cm of new snow accumulation. Freezing levels around 400m. 

Tuesday: Continued snowfall, another 5-10 cm of accumulation. Light to moderate winds from the southwest. Freezing levels at valley bottom.

Natural and human triggered avalanches are likely today. If you do observe any avalanche activity please let us know by submitting to the Mountain Information Network! ?

Over the past few weeks, we have been concerned about a potential persistent weak layer in the region. While most of the relevant observations have come from the neighbouring Sea To Sky region, similar types of avalanches were observed in northern parts of the region over a week ago. We suspect it would still be possible to trigger avalanches on this layer in isolated terrain features such as shallow rocky start zones around treeline elevations. 

Learn more about how this persistent weak layer is developing in our latest forecaster blog!

Persistent cold temperatures may have made cornices facetted and weak, highlighting the importance of avoiding overhead hazard and giving them a wide berth when travelling at ridge crest. Cornice failures can create a large load on the snowpack and trigger persistent weak layers.

A significant storm impacted the region overnight. Heavy snowfall will continue into today with upwards of 40 cm of accumulation expected by the end of the day. Strong southwest winds will create deep deposits of slab in open areas. In sheltered areas, the new snow will form a touchy storm slab or loose dry problem as it is falling on an inherently weak layer formed from prolonged cold temperatures over the past week.

This layer is comprised of near surface facets, a thin sun crust on steep south facing aspects, and surface hoar in isolated areas at treeline and below. In many area, these weak crystals are sitting on a firm bed surface of hard, wind effected snow and old windslabs.

A weak layer of facets (sugary snow) may be found over a crust that formed in early December (down 80-200 cm). In the neighbouring Sea to Sky region this layer has been particularly reactive at treeline and low alpine elevations, between 1800-2100 m. We have seen a decreasing trend in avalanche activity on this layer as it has transitioned into a tricky low-probability high-consequence problem (see the problem description and travel advice for suggestions).

The lower snowpack is well settled with several early season crusts decomposing. Snowpack depth at treeline ranges from 160-250cm.

• Avoid all avalanche terrain during periods of heavy loading from new snow and wind.
• Use conservative route selection. Choose simple, low-angle, well-supported terrain with no overhead hazard.
• Be aware of the potential for large, destructive avalanches due to the presence of deeply buried weak layers.
• Be especially cautious near rock outcroppings, on steep convexities and anywhere the snowpack feels thinner than average.