Avalanche Forecast

Issued: Feb 29th, 2016 3:00PM

The alpine rating is considerable, the treeline rating is considerable, and the below treeline rating is moderate. Known problems include Storm Slabs and Persistent Slabs.

Avalanche Canada pmarshall, Avalanche Canada

Touchy and growing storm slabs will keep avalanche danger elevated this week. Riding should be great, but a conservative approach is recommended. Stick to simple terrain.

Summary

Confidence

Moderate - Forecast snowfall amounts are uncertain

Weather Forecast

Tuesday: Periods of snow 10-15 cm. The freezing level is near 1400 m and winds are moderate to strong from the SW. Wednesday: 10 cm of snow should accumulate before tapering off throughout the day. The freezing level is near 1400 m and ridge winds ease from moderate W-NW to light. Thursday: Periods of snow. The freezing level remains near 1400 m and wind increase to moderate from the SW.

Avalanche Summary

Numerous intentionally-triggered size 1-1.5 storm slabs were reported on Sunday. Most of these were from unsupported and wind-loaded features. Additionally, there were reports of loose dry sluffing in steep terrain, and a couple natural size 2 storm slabs from big alpine slopes. These fresh storm slabs should increase in size and likelihood and become much more widespread as they build throughout the week.

Snowpack Summary

30-40 cm of new storm snow sits on a crust on solar aspects and lower elevation terrain, and surface hoar on shady and sheltered slopes. Touchy new wind slabs are likely in exposed lee terrain at and above treeline. A weak layer of surface hoar and/or a sun crust buried February 21 is now 40-75cm below the surface. Where it exists, this layer may become reactive to human triggers as the overlying slab develops. The surface hoar and/or crust layer buried February 10 is now down 75-120cm. This layer was less reactive over the weekend with cooler temperatures, but remains a concern for large triggers like cornice falls or a smaller slide in motion. Cornices are large and potentially weak and should be avoided if possible.

Problems

Storm Slabs

An icon showing Storm Slabs
Fresh storm slabs are developing and may be slow to bond to and underlying crust and/or recently buried surface hoar layer. Triggering is more likely in steep wind-loaded terrain (N-SE aspects).
Use ridges or ribs to avoid pockets of wind loaded snow.>Be cautious as you transition into wind affected terrain.>Choose well supported terrain without convexities.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely - Very Likely

Expected Size

1 - 4

Persistent Slabs

An icon showing Persistent Slabs
Minimize exposure to sun exposed slopes when the solar radiation is strong.>Be aware of the potential for large, deep avalanches due to the presence of buried surface hoar.>Caution around convexities or areas with a thin or variable snowpack.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 5

Valid until: Mar 1st, 2016 2:00PM