Avalanche Forecast

Issued: Jan 20th, 2014 4:00PM

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

tim haggarty, Parks Canada

Waterton Lakes.

Solar heating will continue to be the main variable affecting the snowpack for the next few days. Wind effect and crusts have created difficult downhill conditions on all but wind sheltered and shaded slopes. Hazard is low likelihood high consequence

Summary

Weather Forecast

Generally warm temperatures with freezing levels near 1500m through Thursday then rising towards 2300m Friday. Very dry conditions will persist with some thin cloud. A weak front slips down form the North on Wed which could bring minor amounts of precip and a lull in the steady moderate West winds . Very little snow remains available for transport.

Snowpack Summary

Warm temperatures and sun have created variable crusts on SE through SW slopes. West winds have stripped snow from any exposed features and created hard windslabs behind. 30 to 40 cm above the ground weak, facetted snow remains a concern on steep or unsupported planar slopes and in the many thin areas found with this highly variable snowpack.

Avalanche Summary

There has been very little avalanche activity observed in the Park in the last week however avalanches associated with the deep persistent slab have been triggered by a few parties in the neighboring regions. Although avalanche activity may decline in this stable period, remember that this problem will be with us for some time to come

Confidence

Problems

Deep Persistent Slabs

Be conservative with your terrain selection and consider steep or unsupported planar slopes carefully. Assess the snowpack often: the variable nature of the snowpack makes it hard to avoid shallow areas where triggering may be more likely.

Be aware of the potential for full depth avalanches due to deeply buried weak layers.Make observations and assess conditions continually as you travel.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Unlikely

Expected Size

2 - 3

Wind Slabs

These old, hard slabs still deserve respect especially in steep or unsupported terrain. Remember that triggering these surface slabs may create enough load to pull out a larger deep persistent slab. Triggering may be easier in warmer periods.

Be careful with wind loaded pockets. Be aware of wide variation in snowpack depthBe aware of the potential for wide propagations due to the presence of hard windslabs.

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

Elevations: All elevations.

Likelihood

Possible

Expected Size

1 - 2

Cornices

With mild temperatures and strong solar radiation any snow near rocks could easily release. The large load created by a falling cornice could trigger the deep persistent slab.

Pay attention to overhead hazards like cornices.

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

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

1 - 3

Valid until: Jan 23rd, 2014 4:00PM