Avalanche Forecast

Issued: Feb 24th, 2014 7:36AM

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

Peter, Avalanche Canada

Northwest Inland.

A buried persistent weak layer is still lurking and could wake up with forecast sunshine and rapidly rising temperatures.

Summary

Confidence

Fair

Weather Forecast

Tuesday: Mainly sunny. The freezing level is at valley bottom. Winds are light from the SW. Wednesday: Mainly sunny. The freezing level is at valley bottom but alpine temperatures will approach 0 degrees in the southern part of the region. Winds are light from the NW.Thursday: Sunny with a few clouds. The freezing level is at valley bottom. Winds are light from the north.

Avalanche Summary

Several small natural and rider triggered wind slabs were observed on Sunday. Loose snow sluffing was also reported on steep sheltered slopes. Forecast sunshine and warmer temperatures this week may be enough to make the mid February persistent weak layer become reactive.

Snowpack Summary

Outflow winds picked late on Saturday and have likely resulted in reverse loading in exposed terrain. 35-90 cm of settled storm snow overlies a variety of old surfaces including weak facets, surface hoar (more predominant at tree line and below tree line elevations), a scoured crust, wind pressed snow, or any combination of these. Whumpfing, cracking, and reports from the field indicate a very poor bond between the new snow and these old surfaces. Recent snowpack tests give easy or moderate "pops or drops" shears on this persistent weakness and show potential for wide propagation. A lack of activity on this layer is likely because the overlying snow has not settled into a slab due to the recent cold temperatures.

Problems

Persistent Slabs

The mid February persistent weak layer is down between 35 and 90 cm. Forecast solar radiation and warming temperatures could make this problem more reactive.

Minimize exposure to sun exposed slopes when the solar radiation is strong.>Use conservative route selection, stick to moderate angled terrain with low consequence.>Avoid open slopes and convex rolls at and below treeline where buried surface hoar may be preserved.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 4

Wind Slabs

Outflow winds may have redistributed some of the recent storm snow and formed dense wind slabs in unusual places.

Use ridges or ribs to avoid pockets of wind loaded snow.>Be cautious as you transition into wind affected terrain.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 3

Valid until: Feb 25th, 2014 2:00PM