Avalanche Forecast

Issued: Mar 1st, 2024 4:00PM

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

wlewis, Avalanche Canada

Coquihalla, Harrison-Fraser, Manning, Skagit.

While danger ratings are dropping and natural activity may stop, human triggering is still likely

Stick to conservative terrain, avoid large slopes and overhead hazard

Summary

Confidence

Moderate

Avalanche Summary

Avalanche activity was observed Thursday to size 2.5, with the largest slabs reported from wind loaded features. Observations are currently limited, however we expect rider triggering is still likely.

Snowpack Summary

Up to 90 cm of recent snow has been heavily wind affected in exposed terrain. Storm snow sits over wind-affected surfaces and 30 to 60 cm of settling snow in sheltered areas.

Multiple weak layers exist in the upper and mid snowpack. The most concerning weak layer is a widespread crust found down 60 to 100 cm, with weak, faceted snow immediately above it. This layer will need time to adjust to the new snow load.

The storm snow and buried weak layers have produced recent large avalanche activity. Although natural avalanche activity may taper off, it will remain possible to human-trigger it for some time afterward.

Weather Summary

Friday Night

Partly cloudy with 5-10 cm of snow possible early evening. 20-40 km/h southerly winds, Freezing level 1000 m.

Saturday

Cloudy with 5 cm of snow possible, and afternoon sun. 30-40 km/h southerly winds. Treeline temperature -5 °C. Freezing level hovers around 700 m.

Sunday

Cloudy with sunny periods and isolated flurries. Light southeast ridgetop wind. Treeline temperature -6 °C. The freezing level hovers around 900 m.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

Potential for wide propagation exists, fresh slabs may rest on surface hoar, facets and/or crust.
Remote triggering is a concern, watch out for adjacent and overhead slopes.
Brief periods of sun could quickly initiate natural avalanche activity.
Storm slabs in motion may step down to deeper layers resulting in large avalanches.

Problems

Storm Slabs

Deeper and more sensitive slabs exist on north and east facing slopes near ridges. Danger may rise quickly if the sun appears.

Good travel habits are key, minimize your exposure to avalanche terrain and evaluate safe spots with caution.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 2.5

Persistent Slabs

Facets above a crust persists deep in the snowpack most prevalent at treeline elevations. Storm slabs may step down to this layer resulting in very large, destructive avalanches.

Use low-angle simple terrain to help manage this problem.

Aspects: All aspects.

Elevations: Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 3

Valid until: Mar 2nd, 2024 4:00PM