Avalanche Forecast

Issued: Mar 6th, 2018 4:04PM

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

jsmith, Avalanche Canada

Lizard-Flathead.

The sun can pack a punch this time of year. Be aware of signs of deteriorating stability such as snow pin-wheeling down slopes or small point-release avalanching below cliffs.

Summary

Confidence

High -

Weather Forecast

WEDNESDAY: Mix of sun and cloud / Light to moderate southwesterly ridgetop winds / Alpine high of -5 with an above freezing layer of air between 1300-1700 m in some areas of the region.THURSDAY: Cloudy with flurries / Light to moderate southwesterly ridgetop winds / Alpine high of -5 FRIDAY: Mostly cloudy with sunny breaks / Light westerly ridgetop winds / Freezing level rising to around 1600m.

Avalanche Summary

Numerous natural and explosive triggered storm slab avalanches up to size 2.5 were reported on all aspects and elevations in this region over the weekend. On Monday an explosive triggered size 2 wind slab was reported on a northeast aspect near Fernie. Currently, slab avalanches are most likely to be human triggered in wind effected areas.

Snowpack Summary

Last week's storms totaled 100cm of snow accumulation in parts of the region. This storm snow overlies various old surfaces including old hard wind slabs, crusts, facets and more isolated surface hoar. In the upper to mid snowpack, a surface hoar layer buried mid-February is now 80 to 100 cm below the surface on sheltered northerly aspects. Deeper in the snowpack, the widespread mid-December weak layer sits about 200 cm deep. This consists of a crust, facets or surface hoar. Near the base of the snowpack, a crust/facet layer could be awoken from a thin-spot trigger point, or with a very large load like a cornice fall.

Problems

Wind Slabs

Wind slabs are becoming less likely to human trigger. Steep, convex, and rocky areas are most likely spots to trigger these lingering winds slabs.

Use ridges or ribs to avoid pockets of wind loaded snow.Be cautious as you transition into wind affected terrain.Be aware of the potential for wide propagations due to the presence of hard windslabs.

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

Elevations: All elevations.

Likelihood

Unlikely - Possible

Expected Size

1 - 2

Valid until: Mar 7th, 2018 2:00PM