Avalanche Forecast

Archived

Apr 12th, 2019–Apr 13th, 2019

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely.

Below Treeline

Natural avalanches unlikely.

Alpine

Natural avalanches unlikely, human triggered possible.

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

Jasper.

Use caution if venturing up high. New snow and wind could create pockets of windslab.

Weather Forecast

10cm of snow is forecast at the Parker Ridge area starting Saturday morning and increasing in intensity overnight. Treeline will be windy with 20-40 km/h westerlys. Freezing level will be around 1900m with a high of -2C. Expect the same closer to Jasper except with less snow. Note that forecast snow amounts have been inaccurate over the past week

Snowpack Summary

Forecast winds and snow could create windslabs in the alpine. A supportive crust exists to 2,100m on all aspects and extends into the alpine on solar slopes. A winter snowpack remains on N aspects above treeline. At upper elevations a weak faceted layer down 20-50cm remains a concern. The snowpack sits on a weak base of facets and depth hoar.

Avalanche Summary

Signs of cornice failures up to size 2 have been reported and a large serac triggered avalanche was witnessed off the south side of Mt. Kitchner on Thursday. Large whumpfs on the ridge of Mt. Wilcox were also reported on Thursday.

Confidence

Timing, track, or intensity of incoming weather system is uncertain

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.

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.

Loose Dry

Loose Dry avalanches are the release of dry unconsolidated snow and typically occur within layers of soft snow near the surface of the snowpack. These avalanches start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-dry avalanches include point-release avalanches or sluffs.