Avalanche Forecast

Issued: Apr 3rd, 2013 5:00PM

The alpine rating is below threshold, the treeline rating is below threshold, and the below treeline rating is below threshold. Known problems include Loose Wet, Cornices and Wet Slabs.

tim haggarty, Parks Canada

Waterton Lakes.

This is the end of our regular forecast season. Avalanche hazard will persist. Hazard will be higher with heating from rain or sun and will be lowest during cool periods. Spring storms may also bring a return to winter at upper elevations.

Summary

Weather Forecast

None provided for the extended period however visitors may call Waterton Lakes National Park Reception on weekdays at 403 859 2224 for more detailed information. Generally: watch freezing levels closely to determine where heating and weakening of the snowpack is likely by the sun and rain. If more snow arrives watch the bond to the surface crusts.

Snowpack Summary

A surface crust exists on all aspects and at all elevations. The strength of this crust varies with location as it freezes with cooling and weakens with heating. In thin snowpack areas weak layers persist that were created by earlier faceting of mid and basal snow. Weak moist snow may fail as point releases or as slabs over crusts or weak layers.

Avalanche Summary

With strong solar inputs a daily cycle of superficial LOOSE WET AVALANCHES spread to affect all elevations and aspects earlier this week. This same heating also caused many CORNICE FAILURES. A few notable slabs were triggered by cornice failures (large loads) in THIN SNOWPACK AREAS where weak snow has developed in the mid and lower snowpack.

Confidence

Problems

Loose Wet

Depending upon the inputs of heat from rain or sun this activity can be expected everywhere. Travelers must carefully monitor surface conditions and be clear of slopes before crusts break. Use extra caution if there is moist snow over buried crusts.

Be alert to conditions that change with elevation.Plan to be off big slopes before the temperatures rises and the snowpack deteriorates.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 2

Cornices

With warm temperatures, solar heating, or rain to upper elevations cornice failures will occur. These are large triggers and have the potential to create larger avalanches. Minimize your exposure especially during rapid warming.

Pay attention to overhead hazards like cornices.Cornices become weak with daytime heating.

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 3

Wet Slabs

Shallow snowpack areas hold weak mid and lower layers. These areas will be more susceptible to failure with heating but have failed with large loads (such as cornices or loose avalanches) acting as the trigger.

Carefully evaluate and use caution around thin snowpack areas.Caution around convexities or areas with a thin or variable snowpack.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

1 - 2

Valid until: Apr 4th, 2013 5:00PM