Avalanche Forecast

Issued: Mar 1st, 2018 3:33PM

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

ghelgeson, Avalanche Canada

South Coast Inland.

One last shot of snow and wind Thursday night may form shallow wind slabs at upper elevations. Keep a close eye on the effects of the strong sun Friday, it could initiate natural avalanche activity very quickly.

Summary

Confidence

Moderate - Timing or intensity of solar radiation is uncertain on Friday

Weather Forecast

There is potential for a few centimeters of snow on Friday, and then we move into a high and dry period. No significant precipitation is expected for the foreseeable future. FRIDAY: Scattered cloud cover in the morning, cloud building throughout the day, freezing level rising to around 900 m, light east/northeast wind, 1 to 10 cm of snow possible. SATURDAY: Scattered cloud cover, freezing level rising to around 1200 m, light variable wind, no precipitation expected.SUNDAY: A few clouds, freezing level rising to around 1300 m, light west/northwest wind, no precipitation expected.

Avalanche Summary

On Wednesday a natural size 1 wind slab was reported from an east facing feature at 1950 m. Isolated soft wind slabs were also being observed on steep convexities.Several small wind slab avalanches 15 to 25 cm in depth were susceptible to ski cutting Tuesday on north, northeast and east facing features between 1800 and 2000 m.Wind out of the southwest and west picked up on Monday forming very soft wind slabs to size 2 that were reactive to skier traffic.

Snowpack Summary

The region picked up 5 to 10 cm of snow Wednesday night which adds to the 20 to 50 cm that fell over the weekend. Wind over the last few days out of the south, southwest and west formed widespread wind slabs, but these wind slabs are becoming more stubborn and somewhat resistent to human triggering. The February 23 weak layer is now down 30 to 70 cm below the surface. This interface consists of wind hardened snow, facets, a sun crust on solar aspects and surface hoar that is present at and below treeline. Compression tests preformed Wednesday continue to show planar results at this interface. In the southern portion of the region a widespread crust is down 40 to 80 cm below the surface. Well-consolidated snow exists below the crust.Variable winds in the past month have created cornices on many alpine ridgelines. They will become touchier as they grow in size, as temperatures rise, and as the strong late-winter sun shines down upon them on clear days.

Problems

Wind Slabs

Strong wind and snowfall this week has formed slabs that are likely becoming less sensitive to human triggering. Strong southeast wind and 2 to 10 cm of new snow Thursday night may form shallow wind slabs in wind exposed terrain.

Watch for signs of instability like whumphing, hollow sounds, shooting cracks or recent avalanches.Use caution with wind loaded terrain features, especially during periods of active loading.Brief periods of sun could quickly initiate natural avalanche activity.

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

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 2

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 travelling on or below ridges.Watch out for overhead hazards, such as cornices, which could trigger slabs on slopes below.Avoid slopes when the solar radiation is strong, especially if they have large cornices overhead.

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 3

Valid until: Mar 2nd, 2018 2:00PM