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, 2019–Feb 25th, 2019

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

Regions

Kootenay Boundary.

Sheltered terrain offers the best riding, but be cautious on steep unsupported features where triggering slab avalanches remains a concern.

Confidence

Moderate -

Weather Forecast

SUNDAY NIGHT: Clear with a few clouds, moderate northeast wind, alpine temperatures drop to -18 C.MONDAY: Mix of sun and cloud with some isolated flurries possible later in the day, possible accumulations of 5 cm, moderate northeast wind, alpine high temperatures around -15 C.TUESDAY: Mix of sun and cloud, moderate northeast wind, alpine high temperatures around -18 C.WEDNESDAY: Cloudy with scattered flurries and localized accumulations of 5 cm, moderate southeast wind, alpine high temperatures around -12 C.

Avalanche Summary

On Saturday, a few small (size 1-1.5) human triggered slab and loose dry avalanches were reported. One large (size 2.5) naturally triggered persistent slab avalanche was observed on a south aspect near Paulson Summit.On Friday, numerous small (size 1) storm slab avalanches were triggered by riders in steep terrain.Human triggered avalanches were reported everyday between February 12 and 20. Although most avalanches were small (size 1-1.5), some had impressive propagation on buried weak layers (see some examples here and here). Last Tuesday, a notable size 3 persistent slab avalanche occurred on an east aspect at 2000 m. This avalanche was triggered by explosives and failed on the persistent weak layer that was buried on February 7th.

Snowpack Summary

The latest storm brought 15-25 cm of low density snow that now covers variable wind slabs at higher elevations and sun crusts on south-facing slopes. Fresh wind slabs may be forming in exposed terrain.A weak layer of surface hoar (feathery crystals) and a crust that was buried on February 7th is now 30-50 cm deep. This layer has been reactive, and has produced avalanches as large as size 3. Two other surface hoar layers are buried 50 to 80 cm deep the snowpack (referred to as the February 1st and mid-January layers). Although they have not been reactive recently, they are still being monitored by professionals. The lower snowpack is considered generally strong.

Problems

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.

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.