Avalanche Forecast

Issued: Feb 11th, 2017 3:47PM

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

mgrist, Avalanche Canada

Sea To Sky.

Human triggered avalanches remain likely on Sunday in wind-loaded (northerly) features in the alpine. Avoid stiff wind slab areas or wind loaded pockets.

Summary

Confidence

Moderate - Due to the number of field observations

Weather Forecast

Seasonal temperatures and isolated flurries through the weekend. Significant warming Monday onwards.SUNDAY: Mix of sun and cloud / Light, southwesterly winds / Freezing level rising to 1500 m by late afternoon. MONDAY: Sunny with cloudy periods, warming significantly with highs to +2 Celsius / Moderate southeasterly winds / Freezing level around 2000 m. TUESDAY: Mostly cloudy / High temperatures to +3 Celsius / Light-moderate southwesterly winds/ Freezing level around 2200 m.

Avalanche Summary

A few Size 1 avalanches were triggered with explosive control work on Sunday.

Snowpack Summary

40-80 cm of recent storm snow fell with moderate to strong southerly winds and formed variable wind slabs on northerly aspects. Inverted temperatures (warmer at higher elevations) made the slab problem worse. The new snow has buried a wide variety of old snow surfaces including stiff wind slab or wind affected snow at upper elevations, sun crust on steep southerly slopes, surface hoar (up to 10 mm) in sheltered locations. In sheltered ares where the recent storm snow is overlying surface hoar (weak, feathery crystals), you may see increased reactivity on this layer as the storm snow begins to settle into a more cohesive slab. The mid and lower snowpack is generally well settled (strong). However, there remain a number of facet and crust layers that are currently dormant but will require monitoring with additional loading (and warming early next week), especially in shallower, rocky areas.

Problems

Wind Slabs

The warming trend throughout the storm has created a tricky condition where warmer heavy snow is sitting on-top of colder snow, making storm and wind slab avalanches much more likely.

Use caution in lee areas in the alpine and treeline. Recent storm snow has formed touchy slabs.Be cautious as you transition into wind affected terrain.Enter your line well below ridge crests to avoid wind loaded pillows.

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 3

Valid until: Feb 12th, 2017 2:00PM