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

Feb 26th, 2022–Feb 27th, 2022

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

Regions

South Columbia.

There is more than what can be seen at the surface ! Choose low consequence slopes, as wind slabs and persistent slabs remain a concern for riders.

Confidence

Moderate - Uncertainty is due to the timing, track, & intensity of the incoming weather system.

Weather Forecast

A shift in the weather pattern is expected early Sunday as a series of weather systems will move through the region. Moderate to heavy snowfalls, rising freezing levels, and warmers temperatures are expected until mid-week.

Saturday night: Intermittent flurries up to 5 cm. Freezing level returning to valley bottom. Alpine temperatures around -10 C. Moderate southwesterly winds gusting 50 km/h.

Sunday: Snow 5 cm. Freezing level rising to 1000 m. Alpine temperatures around -6 C. Moderate to strong southwesterly winds up to 60 km/h.

Monday: Snow 20-30 cm. Freezing level rising to 1200 m. Alpine temperatures around -2 C. Moderate to strong southwesterly winds.

Tuesday: Snow 5-10 cm. Freezing level rising to 1600 m. Alpine temperatures around -2 C. Moderate to strong southwesterly winds.

Avalanche Summary

A large (size 2) persistent slab avalanche caught a skier by surprise Friday in the Valhallas, while skiing a south-facing alpine slope, previously wind-loaded. Recent wind transport induced a significant cornice fall, which naturally triggered a large slab (size 2.5) at upper treeline in the Selkirks. 

During the last week, very large persistent slabs (size 3) were observed, such as this one near London Ridge and in the Valhallas. They both occurred naturally on south-westerly alpine slopes. These evidences are showing that persistent weak layers had begun to "wake up". 

Snowpack Summary

Last week's extensive northerly winds have created heavily wind-affected surfaces in exposed areas and wind slabs in lee areas. Continued cold temperatures have transformed surface conditions since the latest snow (20-80 cm) about a week ago. A thin sun crust was observed on steep south-facing slopes at lower elevations. Large feathery surface hoar crystals have also been observed in sheltered areas on all elevations. Below ~1200 m, 10-20 cm of snow is now overlying a thick melt-freeze crust. 

Two weak layers exist within the upper snowpack: the mid-February layer (down 50 to 100 cm) and the mid-January layer (down 80 cm). They both consist of surface hoar / melt-freeze crust. Although reactivity of these layers had tapered off lately, they should be treated with caution with this incoming series of snowfalls as they may produce large, unexpected avalanches.

Terrain and Travel

  • Be careful with wind loaded pockets, especially near ridge crests and roll-overs.
  • Be careful with wind slabs, especially in steep, unsupported and/or convex terrain features.
  • Recent new snow may be hiding windslabs that were easily visible before the snow fell.
  • Be aware of the potential for large avalanches due to the presence of buried persistent weak layers.

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.