Avalanche Forecast

Issued: Apr 7th, 2017 4:05PM

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

mbender, Avalanche Canada

Sea To Sky.

Continued snow and wind over the past few days will keep the avalanche danger elevated at upper elevations.

Summary

Confidence

Moderate - Forecast snowfall amounts are uncertain on Saturday

Weather Forecast

SATURDAY: Flurries, accumulation 5-10cm / Moderate southwest wind / Alpine temperature -5 / Freezing level 1400mSUNDAY: Mix of sun and cloud / Light to moderate south wind / Alpine temperature -6 / Freezing level 1300mMONDAY: Flurries / Light southwest wind / Alpine temperature -6 / Freezing level 1300m

Avalanche Summary

Reports from Wednesday and Thursday include explosives triggered storm slabs running size 1.5 - 2, 25-30cm deep. On Monday a few natural cornice releases to size 2.5 were observed running to the bottom of their run outs entraining loose snow only. On Saturday, expect newly formed wind slabs to be reactive to human triggering.

Snowpack Summary

30-50cm of new snow at upper elevations sits on widespread melt-freeze crusts that exist on all aspects and elevations except for high elevation north facing terrain. On all aspects below 2000 m and higher on sun exposed slopes, there may be multiple crust layers in the upper snowpack. Moderate to strong alpine wind from the south will have redistributed the new snow and formed additional wind slabs in the alpine and at tree line. Large overhanging cornices exist primarily on north aspects in the alpine.

Problems

Storm Slabs

The combination of new snow, moderate to strong southerly winds and warm temperatures have created reactive storm slabs. These are expected to especially touchy in the lee of exposed terrain features.

Use ridges or ribs to avoid pockets of wind loaded snow.The new snow will require several days to settle and stabilize.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Cornices

Large cornices may become weak with daytime warming or during periods of stormy weather.

Avoid exposure to slopes that have cornices overheadGive cornices a wide berth when traveling on ridges

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

2 - 3

Valid until: Apr 8th, 2017 2:00PM