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 18th, 2023–Feb 19th, 2023

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

Regions

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

Watch for signs of new wind slab formation on Sunday, especially in any areas which receive more than just light snow flurries. Older, larger wind slabs may also still remain reactive to human triggering in isolated areas. Seek out sheltered terrain to avoid the problem and for better riding opportunities in softer snow.

Confidence

Moderate

Avalanche Summary

On Friday, ski cutting was triggering size 1 loose dry avalanches in steep terrain. A small skier-triggered persistent slab was also reported failing on a layer of surface hoar from late January in a below-treeline feature southwest of Nelson. This appears to be an isolated event in the region but a good reminder that weak layers may remain reactive in isolated areas.

Snowpack Summary

New snowfall will bury a highly variable snow surface which may consist of any of the following: a widespread layer of large surface hoar in wind-sheltered terrain, wind slabs or wind-pressed snow in exposed terrain, and sun crusts on steep solar aspects. A slightly older layer of large surface hoar may be found down another 20-30 cm below the old snow surface.

The middle of the snowpack is generally well consolidated and stiff but does contain some old persistent weak layers. These layers have not produced avalanches in quite a long time and are not currently a concern like the regions to the north, but could wake up with significant storm loading or warming.

The lower snowpack consists of a layer of weak, sugary crystals that have been slowly gaining strength and don't currently appear to present the same problem as the regions to the north and east. However, we continue to track the layer and watch for any signs that it might wake up and produce very large avalanches.

Weather Summary

Saturday night

Clear and dry with increasing cloud cover overnight, moderate NW wind, treeline low around -12 ˚C.

Sunday

Light snow flurries up to 5 cm, moderate to strong SW wind, treeline high around -5 ˚C.

Monday

Light snowfall continuing overnight up to 10 cm, with a break expected Monday morning before the next storm pulse arrives Monday afternoon, moderate to strong W-NW wind, treeline high around -3 ˚C.

Tuesday

Snowfall 15-25 cm overnight and another 10-25 cm during the day, strong SW wind, easing in the afternoon, treeline high around -5 ˚C.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Be careful with wind slabs, especially in steep, unsupported and/or convex terrain features.
  • Pay attention to the wind, once it starts to blow fresh sensitive wind slabs are likely to form.
  • Pay attention to cornices and give them a wide berth when traveling on or below ridges.

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.