Avalanche Forecast

Archived

Apr 3rd, 2024–Apr 4th, 2024

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.

Below Treeline

Natural avalanches unlikely.

Regions

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

The upper snowpack has undergone significant settlement over the past few days. Be on the lookout for freshly formed wind slabs and avoid overhead cornice exposure.

Confidence

Moderate

Avalanche Summary

Numerous natural size 1-1.5 wet loose avalanches observed on the Icefields Parkway on Tuesday.

No new avalanche activity on the Icefields Parkway or Maligne Lake Road Today.

Snowpack Summary

5-10cm of new snow overnight on Tuesday arrived with strong to extreme SW wind building winds slabs at treeline and above. A total of 20-40cm of snow now sits over the March 19th crust which is present everywhere except North aspects above 1900m. Solar aspects have multiple crusts within the upper 30 cm. The Feb 3rd crust interface is down 30-90cm. Basal depth hoar and facets make up the bottom of the snowpack. HS ranges from 50 to 150cm.

Weather Summary

Thursday Mainly cloudy with isolated flurries. Trace precipitation. Wind east: 15 km/h gusting to 40. Freezing level at valley bottom

Friday Cloudy with sunny periods & isolated flurries. Trace precipitation. Wind light to 15 km/h. Freezing level 2000m

Saturday A mix of sun and cloud. Freezing level 2100m

Mountain Weather Forecast is available @ Avalanche Canada https://avalanche.ca/weather/forecast

Terrain and Travel Advice

Wind slabs may be poorly bonded to the underlying crust.
If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.
Avoid freshly wind loaded features, especially near ridge crests, roll-overs and in steep terrain.

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.

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.

Cornices

Cornice Fall is the release of an overhanging mass of snow that forms as the wind moves snow over a sharp terrain feature, such as a ridge, and deposits snow on the downwind (leeward) side. Cornices range in size from small wind drifts of soft snow to large overhangs of hard snow that are 30 feet (10 meters) or taller. They can break off the terrain suddenly and pull back onto the ridge top and catch people by surprise even on the flat ground above the slope. Even small cornices can have enough mass to be destructive and deadly. Cornice Fall can entrain loose surface snow or trigger slab avalanches.