Avalanche Forecast

Issued: Feb 21st, 2018 4:06PM

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

swerner, Avalanche Canada

Sea To Sky.

Natural avalanche activity has tapered but wind slabs continue to be reactive to human triggering. Pay attention to overhead hazards like cornices, especially when the sun is out.

Summary

Confidence

High - The weather pattern is stable

Weather Forecast

Thursday: Mostly sunny with alpine temperatures near -11. Ridgetop winds light from the North.Friday: Overcast with new snow amounts 5-10 cm. Alpine temperatures near -9 and ridgetop winds strong from the southwest. Saturday: Mix of sun and cloud. Alpine temperatures near -9. Light to moderate winds from the northwest.

Avalanche Summary

With the benign weather pattern natural avalanche activity has tapered. However, human triggered wind slabs are possible at upper elevations on most aspects but the north.

Snowpack Summary

Highly variable surface conditions exist with extensive wind effect. In exposed terrain, strong north winds have scoured north facing slopes and loaded south facing slopes. In sheltered terrain, especially in the trees you may be able to find 30-40 cm of low density snow. A crust layer can be found beneath the storm snow on sun-exposed slopes and below 1900 m, which has supported some wide propagations in recent storm slab avalanches.Deeper in the snowpack, avalanche professionals are still monitoring the mid-January crust. This layer is now 150-200 cm deep, but a heavy trigger (cornice?) or the next major storm (warming and loading) could potentially wake up this layer.

Problems

Wind Slabs

Strong winds from various directions (primarily north and east) have blown recent snow into stiff wind slabs at treeline and above.

Sheltered slopes at lower elevations will offer the best riding.Approach steep lee and cross-loaded slopes with caution.Use ridges or ribs to avoid pockets of wind loaded snow.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Cornices

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

Minimize overhead exposure to cornices above, they could trigger a slab from the slope below.Give cornices a wide berth when traveling on or below ridges.

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 2.5

Valid until: Feb 22nd, 2018 2:00PM