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

Mar 3rd, 2020–Mar 4th, 2020

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

Regions

Kootenay Boundary.

Wind slabs will continue to develop with strong wind. Riders are also still triggering the layer of surface hoar buried around 30 to 50 cm. Such avalanches have the potential of injuring, burying, or killing a person. A conservative mindset is crucial to stay safe out there.

Confidence

High -

Weather Forecast

TUESDAY NIGHT: Partly cloudy with isolated flurries, strong west wind, alpine temperature -4 C, freezing level 1500 m dropping to 800 m.

WEDNESDAY: Mix of sun and cloud with isolated flurries, light to moderate northwest wind, alpine temperature -9 C, freezing level 1200 m.

THURSDAY: Mix of sun and cloud, moderate southwest wind, alpine temperature 0 C, freezing level rising to 2000 m.

FRIDAY: Cloudy with snowfall, accumulation 10 cm, moderate southwest wind, alpine temperature -3 C, freezing level 1500 m.

Avalanche Summary

A handful more avalanches were triggered by riders on the February 22 surface hoar layer described in the Snowpack Summary. The avalanches were on north to east aspects, they were 25 to 35 cm deep, and they occurred from 1600 to 2000 m. The avalanches were small (size 1 to 1.5). 

Similar avalanches have been observed in the region for the past week, being generally small to large (size 1 to 2) and between 1800 and 2300 m on northwest to east aspects. This trend is suspected to continue as this layer slowly gains strength.

Snowpack Summary

Wind slabs may be found in lee terrain features at higher elevations due to wind transport from southwest wind. They may be around 10 to 20 cm thick immediately adjacent to ridges.

Around 30 to 50 cm of snow overlies a touchy layer of feathery surface hoar crystals. The layer is most commonly found in open trees (e.g. in this MIN) or sheltered terrain around upper below treeline, treeline, and lower alpine elevations. Check out the latest forecaster blog that offers a deeper dive into these conditions.

An older layer of surface hoar buried on February 13th now sits around 60 to 80 cm deep. This weak layer has been problematic in the east of the region between Nelson and Kootenay Pass. While it is likely gaining strength, there is uncertainty around lingering reactivity of this layer. Shallower avalanches may have the potential to step-down to this layer. 

The remainder of the snowpack is strong and well-settled.

Terrain and Travel

  • Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
  • Be aware of the potential for large avalanches due to the presence of buried surface hoar.
  • Avoid exposure to steep, sun exposed slopes, especially when the solar radiation is strong.
  • If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.

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.