Avalanche Forecast

Archived

Mar 17th, 2023–Mar 18th, 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

Friday's Maligne patrol did not observe anything significant yet this was completed by noon. The afternoon heat may have triggered some slopes after the fact. From March 14-16, the Icefields parkway had numerous medium to large avalanches in the alpine on steep rocky features. Some were cornice triggered and size 3. Small loose wet avalanches were noted in steep solar terrain.

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

Snowpack Summary

15-20cm of new snow from March 13th, with moderate SW winds added to the existing windslab in the immediate lee aspects. The new snow is over a sun crust at low elevations steep southerly slopes and old surface facets in sheltered terrain. The mid-pack is 20 to 40cm of low density facetted snow. The lower snowpack is generally weak with large facets and depth hoar at the base. Snowpack depth varies from 60 to 170cm.

Weather Summary

Saturday will bring clouds with sunny periods, -5 °C, light winds, and 1600 metres freezing level. Sunday will be similar but with 1900 metres freezing level. Expect clouds on Monday, similar temperatures, light winds, and 1700 metres freezing level.

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

Terrain and Travel Advice

If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.
Avoid shallow, rocky areas where the snowpack transitions from thick to thin.
It’s possible for avalanche danger to remain elevated into the early evening hours.

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.

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.

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.