Avalanche Forecast

Archived

Jan 6th, 2020–Jan 9th, 2020

Alpine

Natural and human triggered avalanches likely.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Regions

Waterton Lakes.

A storm beginning Monday night will bring 30-40cm of snow to the park with strong winds driving up the hazard. Small avalanches in the storm snow will have potential to step down to deeper weak layers resulting in large avalanches.

Weather Forecast

Tuesday: Snow and wind! Accumulations may reach 25 cm at Cameron Lake through the day with strong to extreme Southwesterly winds. Freezing level rising to 1500m.

Wednesday: Up to 15cm of snow with winds decreasing to light by the evening and temperatures dropping to -20 in the alpine overnight.

Thursday: Cold and cloudy with isolated flurries.

Snowpack Summary

Recent Strong to Extreme winds have stripped windward slopes creating windslabs in lee areas, under which a thick crust exists to 1800m. The Middle of the snowpack is well settled, but a weak facet/ melt freeze crust still lurks near the base of the snowpack. Cornices have grown large.

The snowpack in the front ranges is much thinner and weaker.

Avalanche Summary

No new avalanches observed in the park over the weekend. This will change with incoming snow.

Confidence

Timing of incoming weather systems is uncertain

Problems

Storm Slabs

Storm Slab avalanches are the release of a cohesive layer (a slab) of new snow that breaks within new snow or on the old snow surface. Storm-slabs typically last between a few hours and few days (following snowfall). Storm-slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.

Deep Persistent Slabs

Deep Persistent Slab avalanches are the release of a thick cohesive layer of hard snow (a slab), when the bond breaks between the slab and an underlying persistent weak layer deep in the snowpack. The most common persistent weak layers involved in deep, persistent slabs are depth hoar or facets surrounding a deeply buried crust. Deep Persistent Slabs are typically hard to trigger, are very destructive and dangerous due to the large mass of snow involved, and can persist for months once developed. They are often triggered from areas where the snow is shallow and weak, and are particularly difficult to forecast for and manage.