Avalanche Forecast

Issued: Mar 28th, 2018 4:55PM

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

Avalanche Canada jmcbride, Avalanche Canada

Wind slabs at higher elevations are the main concern right now especially where these sit on a crust. Remember that the sun packs a punch this time of year and reduce your exposure to sunny slopes if the skies are blue.

Summary

Confidence

Moderate - Wind effect is extremely variable

Weather Forecast

THURSDAY: Mix of sun and cloud. Ridge wind light to moderate, west. Alpine temperature near -5. Freezing level 1600 m. FRIDAY: Flurries. Accumulation 5-10 cm. Ridge wind moderate to strong west. Alpine temperature near -5. Freezing level 1400 m.SATURDAY: Mix of sun and cloud. Ridge wind light, west. Alpine temperature near -4. Freezing level 1600 m.

Avalanche Summary

On Tuesday several natural size 1 wind slabs, storm slabs and dry loose were reported in steep terrain near Golden, mostly on immediate lee (down wind) slopes. Also on Tuesday, a dry loose avalanche stepped down to a deeper weak layer, resulting in a size 2 avalanche. This was on a north aspect near 2500m. On Monday, skiers were able to trigger several wind slabs to size 1.5 on steeper west aspects between 1900m and 2400m. Slabs averaged 25-45cm thickness and were not bonding well to the March 19th sun crust.

Snowpack Summary

At tree line and above, most of the region's upper snowpack consists of 20-40 cm of recent storm snow. Areas just east of Kootenay Lake however have seen closer to 70 cm of storm snow. This snow sits on old wind slabs on northerly aspects, and on crusts on solar aspects and all aspects below 1900 m. Surface hoar layers have been reported on shaded aspects at higher elevations and can likely now be found at approximately 50 cm below the surface.Deeper persistent weak layers from mid-late February as well as January and December layers are generally considered dormant, but could wake up with a surface avalanche stepping down, cornice fall, or a human trigger in a shallow or variable-depth snowpack area. These layers consist of sun crust, surface hoar and/or facets. Facets also linger at the base of the snowpack.

Problems

Wind Slabs

An icon showing Wind Slabs
Winds have created wind slabs at higher elevations. Sunny aspects (south through west) require extra caution due to the presence of a buried sun crust, which is acting as an excellent sliding layer for the recent storm snow.
Give cornices a wide berth when travelling on or below ridges.Avoid freshly wind loaded features.Use caution in lee areas in the alpine and treeline. Recent wind loading has created wind slabs.

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

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 2.5

Valid until: Mar 29th, 2018 2:00PM