Avalanche Forecast

Archived

May 10th, 2019–May 11th, 2019

Alpine

Natural and human triggered avalanches likely.

Treeline

Natural and human triggered avalanches likely.

Below Treeline

Natural avalanches possible, human triggered probable.

Alpine

Natural and human triggered avalanches likely.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches possible, human triggered probable.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Regions

Jasper.

Expect there not to be an overnight freeze well into the alpine for the next couple days. Rock climbing, mountain biking and water sports are an excellent choice as well.

Weather Forecast

Warm and convective with no overnight freezes.

Saturday: Sunny with cloudy periods. Alpine temps: Low 5, High 13. Light west winds. Freezing levels 3600m.

Sunday: Mostly cloudy with 2800m freezing levels and possible showers starting in the afternoon.

Monday: Cloudy with possible showers with up to 4mm Low 2, High 9. Freezing levels 3000m.

Snowpack Summary

Snowpack is becoming isothermal into the alpine on shady aspects. The snowpack has transitioned rapidly from Winter to a summer like snowpack. Little to no overnight freezes are expected.

Avalanche Summary

Since the warming trend there has been an avalanche cycle. Numerous loose wet avalanches up to size 2 have been observed in the alpine and treeline. Near Jasper townsite in shallow snowpack areas several large (size 3) slab avalanches have been observed on North to Easterly aspects in the alpine and running into valley bottoms.

Confidence

Freezing levels are uncertain

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.

Cornices

Cornice Fall is the release of an overhanging mass of snow that forms as the wind moves snow over a sharp terrain feature, such as a ridge, and deposits snow on the downwind (leeward) side. Cornices range in size from small wind drifts of soft snow to large overhangs of hard snow that are 30 feet (10 meters) or taller. They can break off the terrain suddenly and pull back onto the ridge top and catch people by surprise even on the flat ground above the slope. Even small cornices can have enough mass to be destructive and deadly. Cornice Fall can entrain loose surface snow or trigger slab avalanches.