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 22nd, 2019–Feb 23rd, 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, human triggered possible.

Regions

Kootenay Boundary.

Fresh wind slabs may be forming at higher elevations, but the main concern is still persistent slabs at lower elevations.

Confidence

Moderate - Forecast snowfall amounts are uncertain on Saturday

Weather Forecast

FRIDAY NIGHT: 5-10 cm of snow, moderate southwest wind, alpine temperatures drop to -12 C.SATURDAY: Mix of sun and cloud with isolated flurries and localized accumulations of 5 cm, light wind, alpine high temperatures around -10 C.SUNDAY: Sunny with cloudy periods, light wind, alpine high temperatures around -10 C.MONDAY: Mix of sun and cloud with light flurries in the afternoon, light northeast wind, alpine high temperatures around -12 C.

Avalanche Summary

Activity on Thursday was limited to sluffing in steep terrain and some isolated whumpfing on south aspects.Human triggered avalanches were reported everyday between February 12 and 20. Although most avalanches were small (size 1-1.5), some have shown impressive propagation (see some examples here and here).On Tuesday, a notable size 3 persistent slab avalanche occurred on an east aspect between 1800-2100 m. This avalanche was triggered by explosives and it reportedly failed on the persistent weak layer that was buried on February 7th.

Snowpack Summary

A weak storm has brought 10-25 cm of low density snow that now covers variable wind slabs at higher elevations and sun crusts on south-facing slopes.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. These layers are most prevalent below treeline on shady aspects. 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.