Avalanche Forecast

Issued: Mar 12th, 2018 4:32PM

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 Inland.

Sustained winds have produced wind slabs in lee features. High freezing levels and sunny skies are 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

TUESDAY: Partly cloudy, moderate southeasterly winds, alpine temperature 1 C, freezing level 2300 m.WEDNESDAY: Cloudy with light snowfall, accumulation 2 to 5 cm, light to moderate westerly winds, alpine temperature -1 C, freezing level 1400 m.THURSDAY: Mostly cloudy, light to moderate northwesterly winds, alpine temperature -2 C, freezing level 1000 m.

Avalanche Summary

Wind slabs were reactive to skier traffic on Sunday, producing small to large (size 1 to 2.5) avalanches in direct lee features at treeline and alpine elevations.

Snowpack Summary

Sustained southerly winds have produced wind slabs in lee features. This overlies a sun crust on solar aspects and a surface hoar and sugary facet layer on sheltered, shady aspects. Expect to find moist snow on solar aspects and on all aspects below around 1000 m.A surface hoar and crust layer from January is buried around 80 to 140 cm. This layer still has the potential to be triggered from a thin snowpack spot, or with a large trigger like a cornice fall.It is unlikely, but may be possible to trigger very large avalanches on facets at the bottom of the snowpack in steep, rocky, and shallow snowpack areas or with large triggers.

Problems

Wind Slabs

Strong southerly winds have redistributed the recent storm snow and formed touchy wind slabs. These slabs have been reactive to skier traffic.

Avoid steep, rocky, and wind effected areas where triggering slabs is more likely.Approach lee and cross-loaded slopes with caution.

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2.5

Loose Wet

High freezing levels and sunny skies are warming the snowpack, particularly on solar aspects. Pay close attention to the effects of the sun on avalanche terrain and avoid overhead exposure.

Avoid terrain traps such as gullies and cliffs where small avalanches can have high consequence.Watch for signs that the snow is heating up such as pin-wheeling and point-releases below cliffs.Start early to stay off south facing slopes during the heat of the day.

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

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 1.5

Valid until: Mar 13th, 2018 2:00PM