Avalanche Forecast

Issued: Feb 3rd, 2016 8:23AM

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

jsmith, Avalanche Canada

Kootenay Boundary.

Storm slabs continue to settle and gain strength but the deeply buried persistent weak layer remains a concern.

Summary

Confidence

Moderate - Forecast snowfall amounts are uncertain

Weather Forecast

Thursday: Mostly cloudy with isolated flurries, light westerly winds, and freezing levels rising to around 1100m. Friday: Flurries starting with moderate southwest winds, freezing level near 1300m. Saturday: Cloudy periods with scattered flurries and moderate to strong southwest winds. Freezing levels remain around 1300m.

Avalanche Summary

No new avalanche observations from this region.

Snowpack Summary

A storm slab 30-40 cm deep can be found across most of the region. This new snow lies above a variable old surface buried at the end of January. This interface is being reported as a layer of surface hoar at treeline in the Rossland area. However, in most other parts of the region the new snow sits on a rain crust and/or old wind slabs. A weak layer buried mid-January can be found down 45-50cm, however, snow pit tests indicate that this layer is gaining strength. Deeper in the snowpack, the persistent weak layer that was buried earlier in January is now down 80-120 cm and continues to give sudden planar fractures in snowpack tests under moderate to heavy loads.

Problems

Storm Slabs

The storm slab may continue to react to human triggers in isolated terrain where it is sitting on a buried surface hoar layer down 20-30 cm. It has not been as reactive where it is bonding to a rain crust.

Choose well supported terrain without convexities.>Be cautious as you transition into wind affected terrain.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 3

Persistent Slabs

This persistent weak layer is a classic low probability but high consequence problem. Dig down to see if the surface hoar exists in your area.

Be aware of the potential for large avalanches due to the presence of buried surface hoar. >Dig down to find and test weak layers before committing to a big line. >

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

3 - 5

Valid until: Feb 4th, 2016 2:00PM