Avalanche Forecast

Archived

Apr 10th, 2023–Apr 11th, 2023

Alpine

Natural and human triggered avalanches likely.

Treeline

Natural and human triggered avalanches likely.

Below Treeline

Natural and human triggered avalanches likely.

Alpine

Natural and human triggered avalanches likely.

Treeline

Natural and human triggered avalanches likely.

Below Treeline

Natural and human triggered avalanches likely.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches possible, human triggered probable.

Regions

Kananaskis, Bow Valley, Highwood Pass, North 40, Spray - KLakes.

Rain at lower elevations and up to 45cm of new snow will lead to an avalanche cycle. Avoid all avalanche terrain on Tuesday.

Confidence

Moderate

Avalanche Summary

Some small loose wet avalanches have been observed on the Canmore Hill. Visibility has been extremely limited today.

Snowpack Summary

Rain soaked snow at lower elevations with small accumulations of heavy wet snow at treeline. Previous wind has created widespread wind slabs at upper elevations. Persistent weak layers down 20 to 80cm are still a concern and these have produced sporadic avalanche activity over the past week. And of course, who could forget about the November facets/depth hoar! Alive and well, this deep persistent problem is likely to become active with the incoming rain, warm temperatures and possibly heavy accumulations at upper elevations..

Weather Summary

Snow will begin Monday night and continue all day Tuesday. Models disagree on snowfall amounts with anywhere between 15 and 45cm predicted in the next 24 hours. On Tuesday winds will be light to moderate from the SW with temperatures near the 0C. Freezing levels will climb to 2100m, so expect rain below this elevation.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

Be aware of the potential for large, deep avalanches to run full path or even longer.
In areas where deep persistent slabs may exist, avoid shallow or variable depth snowpacks and unsupported terrain features.
Avoid all avalanche terrain during periods of heavy loading from new snow, wind, or rain.
Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.

Problems

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.

Loose Wet

Loose Wet avalanches are the release of wet unconsolidated snow or slush. These avalanches typically occur within layers of wet snow near the surface of the snowpack, but they may quickly gouge into lower snowpack layers. Like Loose Dry Avalanches, they start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-wet avalanches include point-release avalanches or sluffs. Loose Wet avalanches can trigger slab avalanches that break into deeper snow layers.

Persistent Slabs

Persistent Slab avalanches are the release of a cohesive layer of snow (a slab) in the middle to upper snowpack, when the bond to an underlying persistent weak layer breaks. Persistent layers include: surface hoar, depth hoar, near-surface facets, or faceted snow. Persistent weak layers can continue to produce avalanches for days, weeks or even months, making them especially dangerous and tricky. As additional snow and wind events build a thicker slab on top of the persistent weak layer, this avalanche problem may develop into a Deep Persistent Slab.