Avalanche Forecast

Issued: Dec 29th, 2023 4:00PM

The alpine rating is considerable, the treeline rating is moderate, and the below treeline rating is low. Known problems include Persistent Slabs and Deep Persistent Slabs.

ahanna, Avalanche Canada

Purcells, Dogtooth, East Purcell, West Purcell.

Above-zero temperatures in the high alpine today adds to an already complex snowpack situation, with potential to further destabilize buried weak layers. Stick to conservative terrain.

Summary

Confidence

Moderate

Avalanche Summary

Most recent avalanche activity has been from explosive control work in the alpine;

persistent layers stepping down to the ground, running up to size 2 in the Dogtooth range
small wind slabs in the northwest Purcells
ski cuts produced size 1 loose dry in the upper snowpack facets near Invermere

Snowpack Summary

A generally well-settled upper snowpack sits atop a complex snowpack with several layers of note.

A layer of buried surface hoar is down roughly 50 to 70 cm and remains concerning in much of the region. It is less of a concern in areas where a strong, supportive crust exists above the surface hoar layer.

The lower snowpack is typically characterized by sugary, facetted crystals and a crust.

Snowpack depths at treeline average roughly 70-120 cm. However, there is significant variability in both snowpack structure and depths across the region.

Weather Summary

Friday night

Partly cloudy. Light southeast wind. Treeline temperature -8 °C. Freezing level valley bottom with an above freezing layer developing 2300-2700 m.

Saturday

A mix of sun and cloud. Light southwest wind. Treeline temperature -4 °C. Freezing level 900 m with an above freezing layer 2300-2700 m.

Sunday

Mostly cloudy with trace amounts of snow. Light northwest wind. Treeline temperature -4 °C. Freezing level 1000 m.

Monday

Mostly cloudy. Light southerly wind. Treeline temperature -6 °C. Freezing level 700 m.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

Extra caution for areas experiencing rapidly warming temperatures for the first time.
In times of uncertainty conservative terrain choices are our best defense.
Avoid shallow snowpack areas, rock outcroppings and steep convex terrain where triggering is most likely.

Problems

Persistent Slabs

The primary layer of concern in much of the region is a layer of surface hoar down 50-70 cm. If triggered, avalanches on this layer could step down to deeper weak layers.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1.5 - 3

Deep Persistent Slabs

A layer of weak facets near the ground may be reactive to human triggering. Especially in shallow, rocky areas in alpine terrain where the layer is not being capped by a crust.