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

Apr 11th, 2021–Apr 12th, 2021

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 possible, human triggered probable.
Treeline
Natural avalanches possible, human triggered probable.
Below Treeline
Natural avalanches possible, human triggered probable.

Regions

Cariboos.

The spring sun can pack a punch and quickly initiate loose wet avalanche activity on steep slopes. Be ready to back off as the snow surface becomes moist. Lingering wind slabs may remain reactive to human triggers on lee features at alpine and treeline elevations.

Confidence

Moderate - Uncertainty is due to the limited number of field observations.

Weather Forecast

A ridge of high pressure sets up over the province bringing sunny, dry weather. Freezing levels are forecast to steadily rise through the week.

Sunday night: Partly cloudy. Light wind switching east. Alpine temperature around -9. Freezing level valley bottom.

Monday: Sunny. Light to moderate east wind. Alpine temperature around -5. Freezing level 1600 m.

Tuesday: Sunny. Moderate east ridgetop wind. Alpine temperature around -2. Freezing level 2000 m.

Wednesday: Sunny. Moderate to strong east ridgetop wind. Alpine temperature around +1. Freezing level 2800 m.

Avalanche Summary

We have not received any reports of avalanche activity since Wednesday when the North Rockies Field team reported and wind slab size 1 from an East aspect at treeline. Since Friday wind slabs have been reported to be stubborn.

In neighboring North Columbia region, wind slabs have shown quite limited reactivity in the last couple of days, the odd ski cut producing size 1-1.5. A couple of natural cornice failures size 2.5 did not trigger slabs on slopes below.

Snowpack Summary

20-40 cm of recent snow may have formed pockets of wind slab on leeward slopes and behind terrain features. On North aspects in the alpine, the recent snow sits on dry wintery snow surfaces and possibly surface hoar on wind-sheltered slopes. Elsewhere, it sits on a series of melt-freeze crusts on all aspects below 1900 m and southerly aspects to mountain top. Reports indicate snow is bonding well at these interfaces.

The recent warm weather is expected to have helped old persistent weak layers heal, including a few crusts buried over the last month as well as a facet layer 150 cm deep from the mid-February cold snap.

Terrain and Travel

  • Be careful with wind slabs, especially in steep, unsupported and/or convex terrain features.
  • Be aware of the potential for loose avalanches in steep terrain where snow hasn't formed a slab.
  • Avoid exposure to steep, sun exposed slopes, especially when the solar radiation is strong.
  • Use extra caution around cornices: they are large, fragile, and can trigger slabs on slopes below.

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.

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.

Loose Wet

Loose Wet avalanches are the release of wet unconsolidated snow or slush. These avalanches typically occur within layers of wet snow near the surface of the snowpack, but they may quickly gouge into lower snowpack layers. Like Loose Dry Avalanches, they start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-wet avalanches include point-release avalanches or sluffs. Loose Wet avalanches can trigger slab avalanches that break into deeper snow layers.