Avalanche Forecast

Archived

Apr 3rd, 2024–Apr 5th, 2024

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 unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Regions

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

More snow is forecast overnight but the warm temps and lack of a freeze on Wednesday have made travel challenging. Pay close attention to the quality of the freeze overnight and incoming snow over the next 24hrs. Avalanche danger can change quickly at this time of year based on solar radiation and rapid loading from snow and or rain. Lots going on in "Spring" but need a good freeze to help get the snowpack back to a more user friendly state.

Confidence

Moderate

Avalanche Summary

One new sz 2.5 deep persistent wet slab was observed on a north aspect in the Buller Mountain slide path control zone. The slide was around 2000m in elevation and in 35deg terrain on a north aspect. It was 100m with and up to 1m deep in places. There were also numerous loose wet avalanches in the region from steeper terrain below treeline.

Snowpack Summary

Warm temps, a minimal overnight freeze and some rain on Wednesday have dramatically changed the winter landscape out there at the moment. 10-15cm of wet heavy snow fell at 1800m with rain below this elevation. Winds were generally light but we did see the snowpack become iso-thermal in some shallow areas and trigger full depth avalanches. The chance for some dry snow exists in the upper elevations but getting up to it will be a challenge until the temperatures cool. Suspect there has been some new windslab development in the alpine but forecasters were not in the field on Wednesday.

An important thing to consider at this time of year is the Quality of the freeze overnight and how much solar radiation is forecast during the day. Avalanche can change from low in the cool mornings to high in the hot afternoons. The timing of this change is important to monitor so plan you trips with these factors in mind.

Weather Summary

Temperatures are forecast to cool overnight with 10cm of snow falling under the influence of an upslope system and another 5cm throughout the day on Thursday. The freezing level is forecast to drop overnight and be around 1800m for the next 24hrs.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

Fresh wind slabs will likely form throughout the day, diligently watch for changing conditions.
Recent wind has varied in direction so watch for wind slabs on all aspects.
Conditions may have improved, but be mindful that deep instabilities are still present.
The more the snowpack warms-up and weakens, the more conservative you`ll want to be with your terrain selection.
Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet

Problems

Wind Slabs

Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind 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.

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.