Avalanche Forecast

Issued: Jan 28th, 2016 4:03PM

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

grant statham, Parks Canada

Banff Yoho Kootenay.

The current storm will taper overnight and end by Friday morning, when temperatures cool significantly. However, unstable slabs will continue to exist, and careful snowpack evaluation and route finding will be critical over the next few days.

Summary

Weather Forecast

The current storm will continue overnight, tapering early on Friday morning. At this time, the upper level flow will rotate slightly into a NW orientation, and we should expect to see clearing and cooling trend starting on Friday. So, expect another 5-10 cm overnight Thursday, then down to -15 and clearing by Friday morning with strong west winds.

Snowpack Summary

The current storm has so far deposited 15 cm of snow in the last 24-hours, along with strong SW winds and warm temperatures - this combination is creating unstable slabs that overlie a weak layer almost 50 cm below the surface. In some areas, moist surface snow adds to the load and many whumphs were observed today confirming the unstable situation.

Avalanche Summary

Minimal avalanche activity observed today, which is surprising considering the conditions. Several wet loose avalanches were noted in the valley bottoms, and some wet debris was observed in several avalanche paths. Consider that the visibility was poor, so our confidence in these observations is low.

Confidence

Due to the number of field observations

Problems

Wind Slabs

We are in the midst of a storm cycle - new snow, strong winds and warm temperatures have created windslabs that make for poor skiing and easy triggering. Avoid avalanche terrain for the next 24-hours.

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

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 3

Persistent Slabs

Close to 50 cm of settled snow now overlies the Jan 4 layer of surface hoar and facets. This layer is visible in snow profiles, and tests show moderate, sudden planar shears. Watch for this problem in open glades and slopes near and below treeline.

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

2 - 3

Valid until: Jan 29th, 2016 4:00PM