Avalanche Forecast

Archived

May 12th, 2019–May 13th, 2019

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.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Regions

Jasper.

Deep avalanche problems are waking-up with warm temperatures resulting in numerous large avalanches. If you go exploring the alpine make sure there has been a good overnight freeze and be out of avalanche terrain before the heat of the day.

Weather Forecast

For Parker Ridge Area

Monday: Cloudy with sunny periods. Treeline temperature: High 9 C. Light ridge wind. Freezing level: 3000 metres.

Tuesday: Showers. Precipitation: 9 mm. Treeline temperature: Low 1 C, High 7 C. Ridge wind southwest: 15-35 km/h. Freezing level: 2800 metres.

Wednesday: Cloudy with sunny periods and isolated wet flurries.

Snowpack Summary

Where snow still exists below treeline, expect slush. At treeline there is still snow on shady aspects but quickly becoming slushy during the day. In the alpine a fresh dusting of snow is being moved around by SW winds and crusts and other deep persistent slab problems are resulting in avalanches due to daytime heat and minimal refreezes overnight.

Avalanche Summary

Since the warming trend started on Friday there has been a widespread avalanche cycle. Numerous loose wet avalanches up to size 2 in the alpine and treeline. Several slab avalanches and cornice failures to size 3.5 have been observed in the alpine on all aspects but predominantly on NE to NW aspects .

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.