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

Jan 28th, 2023–Jan 29th, 2023

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

Kootenay Boundary, Bonnington, Kootenay Pass, Norns, Rossland, South Okanagan, Ymir, Moyie, St. Mary.

Watch for wind affect in unexpected places. Northerly winds will redistribute snow into wind slabs on south facing terrain features.

Continue to be wary of thin start zones and head to supported terrain.

Confidence

Moderate

Avalanche Summary

On Friday small natural and skier triggered wind slabs were reported throughout the region.

Avalanches on the persistent and deep persistent weak layers have not been reported within this region recently. However operators further north in the Selkirks continue to report natural and human triggered avalanches on these buried weak layers.

Snowpack Summary

10-20 cm of wind distributed new snow can be found at the surface, over wind effected surfaces on north facing slopes and a melt freeze on sun affected south facing slopes. The upper snowpack contains several weak layers, with up to 3 surface hoar layers in the upper 70 cm. The primary concern is the early January surface hoar (40-80 cm deep). Observations suggest that this layer is rounding and beginning to bond but may still be reactive in sheltered and shaded terrain features.

A thick melt freeze crust from Boxing Day is buried 70-100 cm deep. This layer is helping to cap our lower snowpack weaknesses but is a concern at higher elevations where this crust begins to thin and becomes less supportive.

The lower snowpack contains weak and facetted grains from November. Triggering an avalanche on this weakness is unlikely. Concern remains for heavy loads such as cornice falls, machine triggers or step down avalanches. Thin snowpack areas where weak layers sit closer to the surface should still be treated as suspect. Check out the latest forecaster blog on these deep weak layers here.

Weather Summary

Saturday Night

Mostly clear skies overnight with trace accumulations possible. Moderate northeast winds. Freezing levels below valley bottom.

Sunday

Sunny with no snowfall expected. Moderate northeast winds continue, alpine high temperatures of -15°C.

Monday

Sunny with increasing afternoon cloud. Winds switch to moderate westerlies. Alpine high of -14°C.

Tuesday

A mix of sun and cloud. Moderate westerlies. Alpine high of -10°C.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
  • Carefully assess open slopes and convex rolls where buried surface hoar may be preserved.
  • In areas where deep persistent slabs may exist, avoid shallow or variable depth snowpacks and unsupported terrain features.

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.