Avalanche Forecast

Archived

Apr 8th, 2023–Apr 9th, 2023

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

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 possible, human triggered probable.

Below Treeline

Natural avalanches possible, human triggered probable.

Regions

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

We are starting to see spring win the snowpack war. The cost of this victory will be a period (now) of an unpredictable snowpack with large avalanches becoming the norm. Give the big, steep lines the space and respect they deserve. Instead, enjoy the mellow slopes or the walking alpine tours.

Confidence

Moderate

Avalanche Summary

Nothing was reported today (as of 3pm). We didn't get a field trip in today, so don't put a lot of weight on the lack of observations.

Snowpack Summary

Once again the warmth is lingering overnight. Valley bottoms are almost above zero 24hrs a day and freezing levels are creeping higher and higher. With the warmth penetrating deeper and deeper into the snowpack we are anticipating a continued weakening of the snowpack. There will be light surface recovery, but the mid pack will retain some of the heat from the day. This is the start of the freeze thaw cycle we've all been waiting for. Unfortunately this means a touchy snowpack for the next while. The pesky Nov deep persistent problem appears to be waking up and as expected, its causing lots of trouble. It will become more reactive as the mid-pack warms up.

Weather Summary

Tomorrow will see the warm weather continue (as it should! enough his enough). Temperatures on Saturday were above freezing for most of the day, and a marginal re-freeze is expected tonight. Saturday's high will be just above zero, but when the solar is factored in it will be much warmer. We may get a few flurries along the way, but not much only a few flakes here and there. Winds will continue to be from the SW and generally light/moderate(20-30km), but gusting into the strong(50km) range.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

In areas where deep persistent slabs may exist, avoid shallow or variable depth snowpacks and unsupported terrain features.
Minimize exposure to sun-exposed slopes when the solar radiation is strong.

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.

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.