Avalanche Forecast

Archived

Mar 15th, 2023–Mar 16th, 2023

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches unlikely.

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 possible, human triggered probable.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Regions

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

Wind slab development has continued over the past 24 hours with solar warming increasing the sensitivity of this problem. Natural wind slabs have stepped down to the deep persistent layer in many locations making conservative terrain choices essential as the basal weakness starts to wake up. Expect avalanche activity to increase Friday - Sunday, particularly at lower elevations, as the temperature and solar radiation rise.

Confidence

Moderate

Avalanche Summary

Icefields parkway- Numerous natural wind slab avalanches stepping down to the deep persistent problem up to size 3 above treeline on all but S-SW aspects. Size one dry loose/ wet loose activity observed in steep terrain at all elevations with most activity occurring on solar aspects. Natural activity notably increases as you head south from the Parkers Ridge area.

No patrol of the Maligne Lake area today.

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

Snowpack Summary

15-20cm of recent snow has been redistributed by SW wind creating wind slabs above treeline. These fresh wind slabs sit over a sun crust on low elevation steep southerly slopes, old wind slab in expose areas, and 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

Thursday

A mix of sun and cloud.

Precipitation: Nil.

Alpine temperature: High -8 °C.

Ridge wind light to 15 km/h.

Freezing level at valley bottom.

Friday

A mix of sun and cloud.

Precipitation: Nil.

Alpine temperature: Low -11 °C, High -6 °C.

Ridge wind light to 15 km/h.

Freezing level: 1500 metres.

Saturday

Cloudy with sunny periods.

Precipitation: Nil.

Alpine temperature: Low -12 °C, High -5 °C.

Ridge wind southwest: 10 km/h.

Freezing level: 1700 metres.

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.

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.

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.

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.