Avalanche Forecast

Issued: Feb 4th, 2016 9:00AM

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

jsmith, Avalanche Canada

South Rockies.

New snow and wind have created fresh wind slabs that are ripe for human triggering.

Summary

Confidence

Low - Timing, track, or intensity of incoming weather system is uncertain

Weather Forecast

Expecting 5-10cm of snow Friday and another 5-10cm on Saturday.Â This will be accompanied by moderate to strong southwesterly winds and rising freezing levels to around 1300m.Â Things cool off and dry out on Sunday.

Avalanche Summary

No new avalanche observations from Wednesday, but we expect human triggered avalanches to occur on Thursday due to new snow and wind.

Snowpack Summary

10-20cm of new snow overnight with light to moderate southwesterly winds have created fresh wind slabs ripe for human triggering in the alpine and exposed treeline. A persistent weak layer of buried surface hoar can be found at variable depths depending on elevation. For example our field team found it down 45 cm at 1850 meters and down 90 cm at 2150 meters in the Crown Mountain area, where compression tests gave hard sudden planar results. A weak crust/facet layer from early-December can typically be found down over 1m. It has become difficult to trigger this layer but it is still reactive in snowpack tests suggesting that it remains capable of wide propagations and large destructive avalanches. Below 1700m the most recent snow hides a melt-freeze crust.

Problems

Wind Slabs

New snow and wind have created touchy wind slabs in alpine and exposed treeline areas.

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

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

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 3

Persistent Slabs

A persistent weak layer of buried surface hoar on the west side of the region and a buried crust/facet combination on the east side of the region continues to be a concern for human triggering in thin spots where the layer is closer to the surface.

Be aware of the potential for large, deep avalanches due to the presence of buried surface hoar.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Unlikely - Possible

Expected Size

3 - 5

Valid until: Feb 5th, 2016 2:00PM