Avalanche Forecast

Archived

Apr 29th, 2019–Apr 30th, 2019

Alpine

Below Threshold.

Treeline

Below Threshold.

Below Treeline

Below Threshold.

Alpine

Below Threshold.

Treeline

Below Threshold.

Below Treeline

Below Threshold.

Alpine

Below Threshold.

Treeline

Below Threshold.

Below Treeline

Below Threshold.

Regions

Waterton Lakes.

25cm of recent storm snow is sitting on a spring snowpack consisting of thick crusts and moist snow on most aspects. Keep an eye on how it is being affected by wind and sun over the next few days.

Weather Forecast

A mix of sun and clouds over the next few days with the potential for afternoon flurries. Freezing levels rising to around 2000m during the heat of the day, and winds increasing on Wednesday

Snowpack Summary

In most areas we are seeing 25cm of recent storm snow sitting on a typical spring snowpack (a thick crust over moist well bonded snow). The exception is high North facing terrain where temperatures have stayed cold and a winter snowpack remains, with facets continuing to linger at the base. Cornices remain large on alpine ridgetops.

Avalanche Summary

One cornice triggered 2.5 deep persistent slab out of unsupported high north facing terrain above Wall lake was observed on Monday.

Confidence

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.

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.