Avalanche Forecast

Archived

Apr 13th, 2024–Apr 14th, 2024

Alpine

Natural and human triggered avalanches likely.

Treeline

Natural and human triggered avalanches likely.

Below Treeline

Below Threshold.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Below Threshold.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely.

Below Treeline

Below Threshold.

Regions

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

Forecasted rating is for the warmest part of the day. Pay attention to the overnight freeze. Either finish the trip, or abort the mission before it warms up.

Helpful hint: the alpine is often sun exposed later into the evening, and earlier the following day than expected. Sometimes alpine freezes aren't as good as valley bottom.

Confidence

High

Avalanche Summary

As of 3pm, a couple of alpine slab avalanches were noted from yesterday's warming. Likely cornice, or solar input being the trigger. With lots of day left, we're expecting to receive reports of loose wet, wind slab and possibly wet slab avalanches.

Snowpack Summary

Below treeline snow depths and quality took a hit today. Lots of melting and an isothermic (slushy) snowpack by mid afternoon. With freezing levels over 3000m, expect temperature and sun crusts to be creeping onto all aspects. North, NE and E aspects may be less affected than the others due to the late day warming. Alpine windslabs have settled out with the warmth.

Weather Summary

Sunday will be slightly warmer the today. Overnight will see -6 as the low, with a daytime high of +6. Saturday's forecasted high was +3, but the actual temperature was +10 by 3pm. That's a significant difference, expect the same pattern on Sunday. Skies will be clear and winds will be light from the SW.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

The more the snowpack warms-up and weakens, the more conservative you`ll want to be with your terrain selection.
Avoid thin areas like rock outcroppings where you're most likely to trigger avalanches failing on deep weak layers.
Use caution above cliffs and terrain traps where even small avalanches may have severe consequences.

Problems

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.

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.