Avalanche Forecast

Archived

Mar 13th, 2025–Mar 14th, 2025

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 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.

There will be short term closures for Avalanche Control on the Icefields Parkway on Friday March 14th. Check 511.

20-30cm of snow fell over Jasper on Thursday. Use caution as the snowpack has almost doubled in the past week.

Confidence

Moderate

Avalanche Summary

No new Avalanches were observed on Thurdsay due to poor visibility. On Monday, observations on the Icefields Parkway corridor revealed widespread natural avalanche activity from during the storm. Large slab avalanches, up to size 3.5, consisted of a mix of storm slab and persistent slab, with occasional step-downs to deeper instabilities.

Snowpack Summary

A further 20-30cm cm of new snow fell on Thursday brining new snowfall amounts to around 70-80cm. Below this fresh snow, the snowpack is complex, with multiple crusts and facet layers creating persistent weak layers. The bottom of the snowpack consists primarily of weak facets and depth hoar.

Weather Summary

Friday

Cloudy with sunny periods and isolated flurries.

Precipitation: Trace.

Alpine temperature: High -11 °C.

Ridge wind west: 10-25 km/h.

Freezing level at valley bottom.

Saturday

Cloudy with sunny periods and isolated flurries.

Precipitation: Trace.

Alpine temperature: Low -19 °C, High -9 °C.

Ridge wind southwest: 10-20 km/h.

Freezing level at valley bottom.

Terrain and Travel Advice

Use conservative route selection. Choose simple, low angle terrain with no overhead hazard.
Avoid exposure to overhead avalanche terrain; avalanches may run surprisingly far.
Recent wind has varied in direction, so watch for wind slabs on all aspects.

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.

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.