Avalanche Forecast

Issued: Mar 10th, 2018 4:40PM

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

jsmith, Avalanche Canada

Lizard-Flathead.

Wind slabs in lee features below ridgetops may still be reactive to human triggers on Sunday.

Summary

Confidence

High -

Weather Forecast

SUNDAY: Sunny / Light southwesterly ridgetop winds / Freezing level rising to around 2300 m.MONDAY: Sunny / Light southwesterly ridgetop winds / Freezing level rising to around 2400 m.TUESDAY: Sunny / Moderate to strong southwesterly ridgetop winds / Freezing level rising to around 3000 m.

Avalanche Summary

A widespread natural avalanche cycle occurred near Fernie on Friday. Numerous storm slabs up to size 2.5 were reported primarily on north and northeasterly aspects between 1800-2100 m. These storm slabs will become less of a concern in the coming days but the forecast warming and sunshine may wake up a deeper weak layer on steep south facing slopes resulting in large and destructive avalanches.

Snowpack Summary

20-30 cm of recent storm snow is settling rapidly. This new snow is sitting on a sun crust on solar aspects. Cornices are large and prone to failure over the weekend caused by forecast sunny skies.In the upper to mid snowpack, a surface hoar or facet layer buried mid-February is now 80 to 110 cm below the surface on sheltered northerly aspects. Deeper in the snowpack, the widespread mid-December and late November weak layers are composed of a combination of crusts and sugary facets which are down 200-300 cm. These layers have been dormant but may be awoken by the warm and sunny weather throughout the weekend or by a large trigger such as a falling cornice.

Problems

Wind Slabs

Isolated wind slabs may still be reactive to human triggers.

Use caution when transitioning into wind affected terrain.Use ridges or ribs to avoid pockets of wind loaded snow.Avoid steep, rocky, wind affected areas where triggering is more likely.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 1.5

Loose Wet

Forecast sunshine may trigger loose wet avalanches on steep south facing slopes.

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

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

Elevations: All elevations.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Mar 11th, 2018 3:00PM