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 24th, 2022–Feb 25th, 2022

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 unlikely, human triggered possible.

Regions

Sea To Sky.

Recently formed wind slabs are expected to be still reactive to human-triggering in exposed high elevation terrain, especially where they overlie a firm crust.

Confidence

Moderate - Uncertainty is due to the extreme variability of wind effect on the snowpack. Uncertainty is due to the fact that persistent slabs are particularly difficult to forecast.

Weather Forecast

A strong ridge of high pressure keeps BC dry until a major weather pattern change takes place beginning this weekend. 

THURSDAY NIGHT: Becoming partly cloudy after midnight, no precipitation, 5-10 km/h westerly wind, alpine low temperature -10 C, freezing level at valley bottom.

FRIDAY: A mix of sun and cloud, no precipitation, 5-10 km/h southwesterly wind, alpine high temperature -5 C, freezing level at 1000 m.

SATURDAY: Increasing cloudiness with light snow beginning in the afternoon, 1-2 cm, 30-50 km/h southerly wind, alpine high temperature -3, freezing level at 1100 m.

SUNDAY: Snow heavy at times, 15-20 cm, 30-50 km/h southerly wind, alpine high temperature -2 C, freezing level at 1200 m.

Avalanche Summary

On Wednesday, a few natural size 1.5 cornice releases were observed on east aspect but did not trigger slab on the slope below. A skier also triggered a size 1 wind slab on a west aspect wind loaded gully feature.

Snowpack Summary

Recent northerly winds have redistributed the snow above the mid-February crust in exposed high elevation terrain which has formed reactive wind slabs and caused extensive wind scouring. This melt-freeze crust is down around 10-30 cm and reported to exist on all aspects and elevations, except for some of the highest elevation polar aspects. Facets have been observed above the crust on northerly aspects.

The late-January crust/facet/surface hoar interface is buried down 40-100 cm. This layer was most reactive between 1700 m and 2000 m. While this layer now appears to be dormant through most of the region, it may still be possible to trigger it at upper treeline or lower alpine features on northerly aspects with a large load like a cornice or in shallow snowpack areas.

Terrain and Travel

  • Be especially cautious as you transition into wind affected terrain.
  • Closely monitor how the new snow is bonding to the crust.
  • 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.