Avalanche Forecast

Issued: Jan 8th, 2014 8:59AM

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

slemieux, Avalanche Canada

South Rockies.

Summary

Confidence

Fair - Intensity of incoming weather systems is uncertain on Saturday

Weather Forecast

Tonight and Thursday: Light precipitation for tonight, a trace during the day tomorrow and it should pick up Thursday night with the arrival of another system . Around 5-10 mm. in water equivalent is forecasted for that period. Light to moderate W and SW winds are forecasted. Freezing levels should remain at the surface.Friday: Light precipitation becoming moderate later, most of it should fall late Friday night and the next day. Moderate W winds for the day. Freezing levels are forecasted to rise close to 1000 m during the day.Saturday: The zonal flow keeps feeding systems to the province. However, this system looks stronger and could leave bigger amounts of precipitation than the previous ones. Temperature are expected to be warmer at first and winds to be strong.

Avalanche Summary

No new avalanches were reported yesterday. A detailed incident report about the Corbin area near miss on Jan. 5th is available here.

Snowpack Summary

The light snow amounts forecasted before the weekend and moderate winds from the W-SW will most likely create new windslabs below ridgetop in the alpine and cover older windslabs from previous wind event. Surface sluffing could also be possible within the new snow in sheltered areas. The facet/crust layer down 80-100 cm at treeline and below treeline and the depth hoar layer in the alpine seems ripe for skier or sledder triggering on E aspects. Multiple recent natural and human triggered avalanches on this aspect is a good sign of this instability. When tested and observed, the surface hoar layer down 70 cm is showing signs of healing (grains are rounding and snowpack test are not as planar as they used to be). The South Rockies field team has posted a new blog with some good info and pictures about the recent avalanche incident and about current conditions. Click here to read it.

Problems

Persistent Slabs

Depth hoar at base of snowpack and/or crust/facets combo layers down 100 cm could still be triggered by skiers and sledders. These layers seem more reactive on E facing slopes.

Dig down to find and test weak layers before committing to a line.>Avoid open slopes and convex rolls at and below treeline where the crust/facet combo or depth hoar exist.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

3 - 6

Wind Slabs

Light accumulations and moderate winds from SW-W will most likely create new windslabs in the alpine below ridgetop. These could be touchy and possible for skiers to trigger.

Be extra cautious in steep lee and cross-loaded features>The recent snow may now be hiding windslabs that were easily visible before the snow fell.>Avoid exposure to terrain traps where the consequences of smaller avalanches could be serious.>

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 4

Valid until: Jan 9th, 2014 2:00PM