Avalanche Forecast

Issued: Jan 29th, 2019 4:51PM

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

kdevine, Avalanche Canada

South Rockies.

A weak layer of surface hoar exists primarily at lower elevations. Be suspicious of steep features such as open glades and gullies.

Summary

Confidence

Moderate - The weather pattern is stable

Weather Forecast

TUESDAYÂ NIGHT - Clear periods / southwest winds, 15-30 km/h / alpine low temperature near -7WEDNESDAY - A mix of sun and cloud / west winds 20-40 km/h / alpine high temperature near -6THURSDAY - A mix of sun and cloud with isolated flurries / southwest winds 20-30 km/h / alpine high temperature near -5 / freezing level 1500 mFRIDAY - Cloudy with scattered flurries, up to 5 cm / southwest winds, 20-30 km/h / alpine high temperature near -3

Avalanche Summary

No new avalanches were reported on Saturday or Sunday.

Snowpack Summary

10-30 cm of recent snow overlies a weak layer of sun crusts on south facing slopes, and surface hoar (feathery crystals) in sheltered areas. The surface hoar is most prominent at treeline and below. Previous strong winds had formed wind slabs over this weak layer. These may to be susceptible to human triggers.Large variability in snow depths still exists in the region, ranging from almost no snow to nearly 200 cm in some areas. For average snowpack areas, expect to find weak and sugary faceted snow around 50 to 100 cm deep, which extend to the ground. This weak bottom half of the snowpack was the culprit in several large avalanches in the region in the past few weeks.

Problems

Persistent Slabs

10-30 cm of snow sits on a weak layer of surface hoar (feathery crystals). This layer is most prominent between 1600-1900 m.

Be cautious on convex rolls around treeline where buried surface hoar may be preserved.Be careful with wind loaded pockets, especially near ridge crests and roll-overs.If triggered the wind slabs may step down to deeper layers resulting in large avalanches.

Aspects: All aspects.

Elevations: Treeline, Below Treeline.

Likelihood

Possible

Expected Size

1 - 1.5

Deep Persistent Slabs

The bottom of the snowpack consists of weak facets and depth hoar (sugary snow). Triggering this layer is becoming less likely, but the consequences remain high as avalanches on this layer will be very large and destructive.

Avoid steep, rocky terrain and shallow snowpack areas where triggering is more likely.Use conservative route selection, choose moderate angled and supported terrain with low consequence.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Unlikely - Possible

Expected Size

2 - 3

Valid until: Jan 30th, 2019 2:00PM