Avalanche Forecast

Issued: Jan 15th, 2018 4:25PM

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

simonhorton, Avalanche Canada

Northwest Coastal.

Reactive slabs will develop throughout the week as snow accumulates. Be prepared to back off if slopes are getting loaded by fresh snow or wind.

Summary

Confidence

Moderate - Intensity of incoming weather systems is uncertain

Weather Forecast

TUESDAY: 5-15 cm of new snow, strong south winds, freezing level dropping to 700 m.WEDNESDAY: More flurries with 10-20 cm of new snow, strong south winds, freezing level steady at 700 m.THURSDAY: Another 10-20 cm of new snow, strong south winds, freezing level steady at 700 m.

Avalanche Summary

Warm alpine temperatures over the weekend caused a natural cycle of large wet loose avalanches (up to size 2.5) on steep solar aspects throughout the region. Some smaller wind slab avalanches were reported in cross-loaded gullies around Bear Pass.

Snowpack Summary

Surface snow is well settled after a weekend of warm alpine temperatures. Wind slabs are lingering on a range of aspects after strong southerly winds on the weekend and outflow winds last week.Below the most recent precipitation, up to 40 cm recent snow overlies several layers of interest in the upper snowpack. These include crusts, surface hoar and facets. A hard crust with associated facets from mid-December sits deeper in the snowpack, about 60 cm down. These layers have been reactive in recent snowpack tests and could potentially be triggered to release large avalanches.The lower snowpack is generally strong, with the exception of areas around Stewart and further north where a basal crust and facets exist.

Problems

Wind Slabs

Strong southerly winds have blown recent snow into fresh wind slabs in lee terrain. Older, more stubborn wind slabs from recent outflow winds may still be reactive around ridge crests and on cross-loaded features at lower elevations.

Be increasingly cautious as you transition into wind affected terrain.Avoid exposure to terrain traps where the consequences of a small avalanche could be serious.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 2

Persistent Slabs

Weak layers buried 60-80 cm below the surface may be reactive in thin snowpack areas or triggered with heavy loads such as a smaller avalanche.

Back off if you encounter whumpfing, hollow sounds, or shooting cracks.Avoid convexities or areas with a thin or variable snowpack.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Unlikely - Possible

Expected Size

2 - 3

Valid until: Jan 16th, 2018 2:00PM