Avalanche Forecast

Issued: Jan 9th, 2017 4:32PM

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

jlammers, Avalanche Canada

Cariboos.

Ridgetop wind speeds are uncertain for Tuesday. If northerly winds are strong, new wind slabs can be expected on all aspects.

Summary

Confidence

Moderate - Wind speed and direction is uncertain on Tuesday

Weather Forecast

Tuesday: Mix of sun and cloud / Moderate north winds / Alpine temperature at -25Wednesday: Clear skies / Moderate north winds / Alpine temperature at -18Thursday: Mix of sun and cloud / Strong northwest winds / Alpine temperature at -14

Avalanche Summary

No new avalanches were reported on Sunday. I'd expect a new round of wind slab activity in response to new snow and wind on Sunday night and Monday. Northerly winds on Tuesday may promote a reverse loading pattern increasing the likelihood of wind slab activity on a variety of aspects.

Snowpack Summary

Up to 20 cm of low density snow fell on Sunday night and Monday. Moderate to strong southwest winds are expected to have shifted these fresh accumulations into wind slabs at treeline and above. Recent snow has also covered old, thicker wind and hard slabs from previous wind events. Persistent and deep persistent weakness in the mid and lower snowpack are giving variable results in snowpack tests, but are generally most touchy in shallow snowpack areas. Recent snowpack tests gave moderate but resistant results on facets and/or surface hoar buried mid-December where it was found down 45 cm, and hard but sudden collapse results on the facet/crust weakness down 116 cm near the base of the snowpack.

Problems

Wind Slabs

New snow on Monday was likely shifted by southwest winds into reactive wind slabs in exposed high elevation terrain. On Tuesday, a switch to northerly winds may promote a reverse loading pattern and fresh wind slabs may exist on all aspects.

Be cautious as you transition into wind affected terrain.Avoid areas where the snow feels stiff or slabby.Be alert to conditions that change with aspect and elevation.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 2

Persistent Slabs

Triggering a weak layer of facets and/or surface hoar buried mid-December may still be possible in parts of the region where the snowpack is shallower. Dig down and test for weaknesses before committing to larger terrain features.

Choose regroup spots that are out of avalanche terrain.Avoid likely trigger spots such as steep and rocky areas with a shallow snowpack.Only expose one person at a time to larger slopes.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Unlikely - Possible

Expected Size

2 - 3

Valid until: Jan 10th, 2017 2:00PM