Dashboard Regions Weather Stations Radar Alerts Glossary
Contact About
Log In

Register for an account and never miss a forecast again!

Register

Avalanche Forecast

Archived

Mar 5th, 2023–Mar 6th, 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

Northwest Inland, Kispiox, Microwave-Sinclair, Ningunsaw, South Bulkley, South Bulkley, Telkwa.

Wind slabs may remain reactive to rider triggers on a variety of aspects due to recently shifting wind direction. The air is cold but the March sun can be strong so avoid exposure to cornices and watch for signs of warming on steep south aspects. Thin rocky areas will remain a concern for triggering deeply buried weak layers in this complex snowpack.

Confidence

High

Avalanche Summary

Prior to the weekend there were numerous reports of natural wind slab and cornice-triggered avalanches up to size 2.

Over a week ago, several large deep persistent slab avalanches were reported in the alpine, including a natural size 3 near Kispiox, a cornice-triggered size 2.5 at Hudson Bay and several explosive controlled size 2-3 near Ningunsaw.

Snowpack Summary

A dusting of new snow may sit over extensively wind affected surfaces at upper elevations. Cornices are large and can be found on a number of aspects. A thin sun crust may be found on steep solar aspects.

In sheltered areas, 40-50 cm of settling snow may be sitting over a layer of small facets and low density snow that feels upside down.

Several other crusts, layers of facets, or surface hoar can be found in the top 150 cm of the snowpack, but have not shown any significant avalanche activity or snowpack test results recently.

The lower snowpack consists of weak, basal facets which may become active with any rapid change or shock to the snowpack, such as heavy loading or dramatic warming. Snowpack depths range from 60 to 280 cm at treeline.

Weather Summary

Sunday night

Scattered cloud. Moderate southeasterly wind. Alpine low -20 ºC.

Monday

Mix of sun and cloud. Moderate southeasterly wind easing to light. Alpine high -17 ºC.

Tuesday

Mix of sun and cloud. Moderate southeasterly wind. Alpine high -16 ºC.

Wednesday

5-10 cm of new snow. Strong southeast wind. Alpine high -12 ºC.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Recent wind has varied in direction so watch for wind slabs on all aspects.
  • Conditions may have improved, but be mindful that deep instabilities are still present.
  • Avoid shallow, rocky areas where the snowpack transitions from thick to thin.
  • Avoid slopes when the solar radiation is strong, especially if they have large cornices overhead.

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.

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.