Avalanche Forecast

Issued: Feb 24th, 2017 3:56PM

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

Avalanche Canada cgarritty, Avalanche Canada

Wind slabs are still lingering on north aspects in the alpine - the same terrain where the best skiing is likely to be found.

Summary

Confidence

High -

Weather Forecast

Saturday: Mainly cloudy with isolated flurries bringing up to 5 cm of new snow, beginning in the afternoon. Winds light to moderate from the southwest. Freezing level to 500 metres with alpine temperatures of -10. Sunday: A mix of sun and cloud with isolated flurries and a trace of new snow. Winds light from the northeast. Freezing level to 700 metres with alpine temperatures of -9. Monday: Cloudy with sunny periods and isolated flurries bringing a trace of new snow. Winds light from the west. Freezing level to 400 metres with alpine temperatures of -10.

Avalanche Summary

Reports of both natural and skier triggered wind slab avalanche activity in the region have tapered off, with small natural and skier triggered loose snow releases dominating Thursday's reports. A MIN report from Wednesday describes a rider involvement in a wind slab avalanche on Fissile Peak, highlighting our ongoing concerns for isolated wind slabs in alpine terrain. On Wednesday in the far north of the region, several wind slabs were observed to have run naturally up to Size 2.5 out of steep, leeward terrain. Recent strong southerly winds were identified as the trigger.

Snowpack Summary

Flurries over Thursday night deposited 1-5 cm of new snow on the surface. Moderate southwesterly winds accompanied the snowfall, making a small contribution to our upper elevation wind slab problem. Below our thin new snow accumulations, recent cool temperatures resulted in up to 5 mm surface hoar growth on the previous snow surface, as well as surface faceting. Sun crusts have also recently been reported to be forming on steep solar aspects. Below the new snow interface, roughly 20-40 cm of recent storm snow appears to be bonding well the widespread mid-February melt-freeze crust. This crust extends as high as 2200 m and is up to 15 cm thick at treeline. Below this crust the mid and lower snowpack are well settled and bonded.

Problems

Wind Slabs

An icon showing Wind Slabs
Watch for wind slabs lingering in the immediate lee of exposed terrain features in the alpine, especially on north-facing terrain.
Use ridges or ribs to avoid pockets of wind loaded snow.Avoid areas where the surface snow feels stiff or slabby.Be cautious as you transition into wind affected terrain.

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Feb 25th, 2017 2:00PM