Avalanche Forecast

Archived

Mar 19th, 2023–Mar 20th, 2023

Alpine

Natural avalanches possible, human triggered probable.

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 possible, human triggered probable.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches possible, human triggered probable.

Regions

Jasper, Brazeau, Churchill, Cirrus-Wilson, Fryatt, Icefields, Maligne, Marmot, Miette Lake, Pyramid.

The region is trending towards spring like conditions. Start early and finish early as the sun is having the strongest effect typically by mid-afternoon. It is wise to choose ice climbs with no overhead hazard and least amount of overall sun exposure.

Confidence

Moderate

Avalanche Summary

Sunday's Icefield patrol noted several low elevation loose wet slides up to size 2. A couple of these were at higher elevation solar aspects. A few deep slabs were also noted on alpine East aspects. Saturday at 5pm a size 2 loose wet roadside slope hit highway 93 burying both lanes for 10metres. A large, likely ice or cornice triggered and solar influenced avalanche, was directly observed at 1:30 in the Stutfield valley. See MIN report.

Don't forget to post avalanche observations to the MIN.

Snowpack Summary

A suncrust has formed on solar aspects at all elevations. This caps off the 15-20cm of new snow from March 13th. Moderate SW winds after March 13th created pockets of windslab on lee aspects. Approximately 20-30cm down is a buried sun crust at low elevations on steep southerly slopes and a surface facet layer in sheltered terrain. The mid-pack is 40 to 80cm of supportive snow. Near the ground it is generally weak with large facets and depth hoar.

Weather Summary

Monday will be sun and cloud, -4 °C, light Northeast winds, and 1700 metres freezing level. Tuesday and Wednesday will be similar except for 2200 metres freezing level on Wednesday.

Detailed weather forecasts from Avalanche Canada: https://avalanche.ca/weather/forecast

Terrain and Travel Advice

Avoid shallow, rocky areas where the snowpack transitions from thick to thin.
Be alert to conditions that change with elevation and sun exposure.

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.

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.