Avalanche Forecast Sea to Sky

Date Issued: Valid Until:

Avalanche Canada swerner, Avalanche Canada

Avalanche Forecast

Thu Feb. 9th ยท 10:13AM

Alpine

Danger Ratings Considerable

Treeline

Danger Ratings Moderate

Below Treeline

Danger Ratings Low
Wind Slabs Wind Slabs
Cornices Cornices

Alpine

Danger Ratings Moderate

Treeline

Danger Ratings Low

Below Treeline

Danger Ratings Low

Alpine

Danger Ratings Moderate

Treeline

Danger Ratings Low

Below Treeline

Danger Ratings Low

Confidence

Fair - Intensity of incoming weather is uncertain on Friday

Weather Forecast

Overnight Thursday: Snow amounts 5-10cms. Ridgetop winds 30-40km/hr from the SE. Friday: Snow amounts 2-5cm. Ridgetop winds 20km/hr from the South. Freezing levels near 1800m. Saturday/Sunday: A ridge will persist through the weekend. Bringing mainly cloudy skies, and accumulations 2-5cms. Freezing levels near 1100m accompanied by moderate SW winds.

Avalanche Summary

On Wednesday natural cornice fall occurred. This large trigger pulled out a size 3 slab avalanche from the slope below. The avalanche occurred on a North aspect @ 1800m. The crown depth was up to 1.5 m, running 800m. No new avalanche activity was reported on Thursday.

Snowpack Summary

Recently, dribs and drabs of snow has fallen on a variety of surface forms. The bond of this new snow will need to be monitored as incremental loading may occur over the next week. The new snow sits on a variety of old surface snow conditions. They consist mainly of crusts that have developed due to melt/freeze conditions, and direct solar impact on steep Southerly aspects. Northerly aspects still host dry, wintery snow. On exposed lee slopes in the alpine there are pencil-4 finger stiff wind slabs. Surface faceting is occurring on sheltered, shady aspects. While shallow, rocky slopes are faceting and weaker; posing a threat to deeper releases. Surface hoar growth is 5-10mm at treeline, and below treeline. These may be our next layers of concern once buried. The Feb 01 (120201) rain crust is down 10-40 cm up to about 2000 meters. The mid-January crust is down between 50-100 cm, and the mid December crust is buried down up to 200 cm. The average snowpack depth at 1650m is near 240cm.

Problems

Wind Slabs

Wind Slabs

Moderate SE winds have formed specific wind slabs in the immediate lee below ridgelines and behind terrain features.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 4
Cornices

Cornices

Cornice fall may trigger slabs on the slopes below. Give cornices a wide berth when traveling on ridgetop, or on slopes below.

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

2 - 6