Avalanche Forecast

Archived

Mar 25th, 2023–Mar 26th, 2023

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Regions

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

The snowpack has gained some strength with the drop in temperatures and cloud cover but convective lift is making it difficult to forecast snowfall amounts on Sunday. Be on the lookout for dry loose avalanches in areas that receive more than 5 cm of snow as new snow will sit over a crust in most locations and be easy to trigger. This thinly buried, breakable crust is making skiing pretty awful in most locations but sheltered areas on true north aspects are still holding some good snow.

Confidence

Moderate

Avalanche Summary

No new activity was observed on the Icefields Parkway today thanks to cloud cover limiting solar effect.

Several wet loose avalanches were observed last week occurring mid to late afternoon at all elevations on southerly aspects. Many of these natural avalanches stepped down to the persistent slab with some triggering the deep persistent slab.

Cornice failures and loose wet avalanches are expected to start back up when the sunshine returns early next week. We may also see some dry loose activity in areas that receive more snow than forecast on Sunday.

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

Snowpack Summary

1-3 cm of new snow (mostly graupel) sits over a breakable sun crust at all elevations on solar aspects. True north aspects are faceted with widespread wind effect in open areas at tree line and above. Approximately 20-50cm down is a persistent slab sitting over a facet layer in sheltered terrain or a weak crust at low elevations / southerly slopes. The lower snowpack is generally weak with large facets and depth hoar at the base.Snow depth varies from 60-150cm.

Weather Summary

Sunday

Flurries.

Accumulation: 2-8 cm.

Alpine temperature: High -6 °C.

Ridge wind light to 15 km/h.

Freezing level: 1400m

Monday

Cloudy with sunny periods and isolated flurries.

Precipitation: Trace.

Alpine temperature: Low -15 °C, High -8 °C.

Ridge wind light to 15 km/h.

Freezing level at valley bottom.

Tuesday

Sunny with cloudy periods.

Precipitation: Nil.

Alpine temperature: Low -11 °C, High -4 °C.

Light ridge wind.

Freezing level: 1600 m

Terrain and Travel Advice

Avoid shallow, rocky areas where the snowpack transitions from thick to thin.

Problems

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.