Avalanche Forecast

Issued: Feb 25th, 2018 4:53PM

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

ghelgeson, Avalanche Canada

South Coast.

Storm slabs up to 55 cm in depth may remain problematic Monday. Choose wind sheltered terrain features while minimizing exposure to both cornices and overhead avalanche paths, the morning sun could initiate natural avalanches.

Summary

Confidence

Moderate -

Weather Forecast

The work week kicks off with a rather disorganized pattern that is not expected to generate any significant snowfall, but a significant change looks to be in store as a vigorous low approaches the South Coast region Wednesday afternoon.MONDAY: Clear skies in the morning, a few clouds building in the afternoon, freezing level around 500 m, light west/northwest wind, no significant snowfall expected. TUESDAY: Broken cloud cover with clearing in the afternoon, freezing level around 900 m, moderate to strong west/northwest wind, trace of snow possible.WEDNESDAY: Overcast, freezing level around 700 m, potentially strong to extreme south/southwest wind, copious amounts of precipitation possible, but the latest model run shows about 15 cm of snow. Stay tuned for more details.

Avalanche Summary

No new activity to report from Saturday. The new snow was reactive to skier activity on Friday, producing small (size 1) dry loose and storm slabs. See this MIN report that talks about storm slabs 10 to 40 cm in depth here.

Snowpack Summary

Around 30 to 40 cm of storm snow fell on Friday and another 10 to 15 cm of snow fell Saturday night into Sunday. Both of these storms had strong southerly winds. All of this snow fell on previously wind-affected surfaces and a sun crust on southerly aspects. The new snow may not bond well to these surfaces and could be reactive to both natural and human triggers.A hard rain crust that extends into alpine terrain is buried about 60 to 100 cm. Reports suggest the snow has a poor bond to the crust with test results showing sudden planar characteristics and a Rutschblock 2 (the whole block failing after standing on it). Monitor the bonds of the new snow as well as the bond of the snow directly above the buried crust. There are no substantial layers of concern below the crust.Also make note of cornices at ridgeline. Variable winds in the past month have produced cornices on all aspects. They will become touchier as they grow in size, as temperatures rise, and as the sun packs a strong punch on clear days. Stand well back of them!

Problems

Storm Slabs

Up to 55 cm of recent storm snow rests on old wind slabs that are not bonding well to a buried crust. Storm snow may remain sensitive to human triggering Monday and will likely need another day to settle and stabilize.

Use caution above cliffs and terrain traps where small avalanches may have severe consequences.Use ridges or ribs to avoid pockets of wind-loaded snow.Start with small terrain features and gather information before committing to bigger objectives.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 2.5

Cornices

Large cornices have formed along ridgelines. Cornices are inherently unstable, unpredictable, and demand respect, especially if the sun is shining.

Give cornices a wide berth when traveling on or below ridges.Firm cornices may pull back into flat terrain at ridgetop if they fail.

Aspects: North, North East, East, South East, South, South West.

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 3

Valid until: Feb 26th, 2018 2:00PM