Avalanche Forecast

Archived

Feb 27th, 2024–Feb 28th, 2024

Alpine

Natural and human triggered avalanches likely.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches possible, human triggered probable.

Alpine

Natural and human triggered avalanches likely.

Treeline

Natural and human triggered avalanches likely.

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 possible, human triggered probable.

Regions

Cariboos, North Rockies, Blue River, Clearwater, McBride, Premier, Quesnel, Sugarbowl, Clemina, North Monashee, McGregor, Renshaw, Robson.

More snow and wind arriving Wednesday means avalanche danger will be High. Persistent slab avalanches are primed for rider triggering.

Confidence

Moderate

Avalanche Summary

Numerous natural and rider triggered storm slab and persistent slab avalanches size 1 to 3 have been reported the past few days in the alpine and treeline elevation bands on all aspects. Most of these occurred on the weak layer of faceted grains 50-80 cm deep sitting on a crust formed in early February. Several were reported as remotely triggered (from a distance).

Expect rider triggered avalanches to be likely as more snow and wind arrives Wednesday through Thursday.

Snowpack Summary

60 to 100 cm of recent snow sits on a variety of layers that it may not bond well to, including surface hoar in wind-sheltered terrain, weak facets, or a hard melt-freeze crust on sun-exposed south and west-facing slopes. The wind has likely formed thicker deposits in lee terrain features near ridges.

A thick and hard widespread crust that formed in early February is buried 50 to 100 cm deep and is found up to around 2400 m. This crust may have a layer of facets above it, which makes it a troublesome avalanche layer.

The remainder of the snowpack is settled.

Weather Summary

Tuesday Night

Cloudy with 5-10 cm of snow. 20 to 50 km/h west and southwest ridgetop wind. Treeline temperature -11 °C.

Wednesday

Cloudy with 5 to 15 cm of snow. 30 to 60 km/h southwest ridgetop wind. Treeline temperature -5 °C. Freezing level 1000 m.

Thursday

Cloudy with 15 to 25 cm of snow. 20 to 40 km/h southwest ridgetop wind. Treeline temperature -6 °C. Freezing level at valley bottom.

Friday

Mostly cloudy with 1 to 3 cm of snow. 15 to 30 km/h southwest ridgetop wind. Treeline temperature -7 °C.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

Only the most simple non-avalanche terrain free of overhead hazard is appropriate at this time.
Shooting cracks, whumphs and recent avalanches are strong indicators of an unstable snowpack.
Fresh snow rests on a problematic persistent slab, don't let good riding lure you into complacency.
Storm slabs in motion may step down to deeper layers resulting in large avalanches.

Problems

Storm Slabs

Storm Slab avalanches are the release of a cohesive layer (a slab) of new snow that breaks within new snow or on the old snow surface. Storm-slabs typically last between a few hours and few days (following snowfall). Storm-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.