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Avalanche Forecast

Mar 21st, 2017–Mar 22nd, 2017
Alpine
3: Considerable
The avalanche danger rating in the alpine will be considerable
Treeline
2: Moderate
The avalanche danger rating at treeline will be moderate
Below Treeline
1: Low
The avalanche danger rating below treeline will be low
Alpine
3: Considerable
The avalanche danger rating in the alpine will be considerable
Treeline
3: Considerable
The avalanche danger rating at treeline will be considerable
Below Treeline
2: Moderate
The avalanche danger rating below treeline will be moderate
Alpine
4: High
The avalanche danger rating in the alpine will be high
Treeline
3: Considerable
The avalanche danger rating at treeline will be considerable
Below Treeline
2: Moderate
The avalanche danger rating below treeline will be moderate

Regions: Sea To Sky.

Forecast snow through the day combined with moderate to strong wind will gradually raise the avalanche danger to considerable in the alpine on Wednesday

Confidence

Moderate - Intensity of incoming weather systems is uncertain on Wednesday

Weather Forecast

WEDNESDAY: Periods of snow, accumulation 10-15cm / Moderate to strong south wind / Alpine temperature -2 / Freezing level 1400mTHURSDAY: Flurries, accumulation 10-15cm / Moderate to strong south wind / Alpine temperature -4 / Freezing level 1300mFRIDAY: Snow, accumulation 15-20cm / Moderate southwest wind / Alpine temperature -3 / Freezing level 1300m

Avalanche Summary

Recent reports indicate both natural and human triggered wind slab avalanches in alpine and tree line lee terrain to size 1.5. On Wednesday, wind slabs may remain reactive to human triggers and at upper elevations the deeper mid-February weak layer continues to present a low likelihood of triggering yet would produce a large avalanche and thus a high consequence if triggered.

Snowpack Summary

Expect an additional 10-15cm of new snow through the day today to add to the 30 cm of storm snow from last weekend, which sits above a widespread rain crust up to 2200m. Thicker wind slabs and large cornices likely exist in alpine terrain. Reports suggest the storm snow is generally well bonded to the crust, and cooling temperatures should help stabilize the upper snowpack. The mid-February crust/facet layer is now 80-120 cm deep and may be up to 200 cm deep in wind loaded terrain. This layer was reactive prior to recent warming events, but now there's some uncertainty as to how long it will remain reactive.

Avalanche Problems

Wind Slabs

Recent southwest and southeast winds have created reactive wind slabs in the lee of terrain features.
Be cautious as you transition into wind affected terrain.Extra caution needed around cornices with current conditions.Use ridges or ribs to avoid pockets of wind loaded snow.

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

Elevations: Alpine, Treeline.

Likelihood: Possible

Expected Size: 1 - 2