Avalanche Forecast

Issued: Mar 11th, 2018 3:45PM

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

mconlan, Avalanche Canada

Northwest Coastal.

Sustained winds have produced new wind slabs in lee features. Increasing freezing levels and sunny skies are intensely warming the snowpack. The best riding will be in areas sheltered from the wind effect and sun, without any overhead exposure.

Summary

Confidence

Moderate - Timing or intensity of solar radiation is uncertain

Weather Forecast

MONDAY: Partly cloudy, moderate southerly winds, alpine temperature 2 C, freezing level 2000 m.TUESDAY: Mostly sunny, light to moderate southeasterly winds, alpine temperature 4 C, freezing level 2200 m.WEDNESDAY: Cloudy with light snowfall, accumulation 5 cm, light southerly winds, alpine temperature 0 C, freezing level 1400 m.

Avalanche Summary

Wind slabs were reactive to skier traffic and natural activity on Saturday. Numerous size 1 to 2 avalanches were reported, generally 10 to 30 cm deep and at treeline and alpine elevations on northerly aspects. Many of these avalanches travelled fast and far when sitting on weak surface hoar. Loose snow was also noted in steep terrain features.

Snowpack Summary

Sustained southerly winds have redistributed the 20 cm of new snow and produced wind slabs in lee features. This overlies a sun crust on solar aspects and 5 to 20 mm surface hoar on sheltered, shady aspects at all elevation bands. Expect to find a melt-freeze crust early mornings and moist snow with warming below around 1500 m.Beneath this, expect layers of crusts, facets, and isolated surface hoar buried 50 to 100 cm below the surface from mid- and late-February. A surface hoar and crust layer from January is buried around 150 to 200 cm.Near the bottom of the snowpack, sugary facets exist in colder and dryer parts of the region, such as the far north.

Problems

Wind Slabs

Strong southerly winds have redistributed the recent storm snow and formed touchy wind slabs in lee features. These slabs overly a weak surface hoar layer in parts of the region, allowing for wide propagation and fast-moving avalanches.

Approach lee and cross-loaded slopes with caution.Avoid steep, rocky, and wind effected areas where triggering slabs is more likely.Use caution above cliffs and terrain traps where small avalanches may have severe consequences.

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Loose Wet

Rising freezing levels and sunny skies will allow for intense warming of the snowpack on solar aspects. Pay close attention to the effects of the sun on avalanche terrain and avoid overhead exposure.

Use extra caution on solar slopes or if the snow is moist or wet.Minimize exposure to steep, sun exposed slopes when the solar radiation is strong.

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

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 1.5

Valid until: Mar 12th, 2018 2:00PM