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 6th, 2022–Mar 7th, 2022

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

Regions

Kootenay Boundary.

March is a notoriously tricky time with snowpack complexity is at its peak and this year is no exception. Recent storm snow sitting on a weak layer has been reactive to human traffic around treeline. We also remain suspicious of several other weak layers deeper in the snowpack.

Confidence

Moderate -

Weather Forecast

Sunday night: Increasing cloud. Moderate northwest ridgetop wind. Treeline temperature around -5 °C. Freezing level valley bottom.

Monday: Partly cloudy. Moderate northwest ridgetop wind. Treeline high around -1 °C. Freezing level rising to 1600 m. 

Tuesday: Flurries up to 5 cm. Light wind. Treeline high around -10 °C. Freezing level valley bottom.

Wednesday: A mix of sun and cloud. Light wind. Treeline high around -12 °C. Freezing level valley bottom.

Avalanche Summary

On Friday and Saturday, several accidentally triggered storm slab avalanches were reported in the northeast of the region. These avalanches were:

  • Large, ranging from size 2-3
  • Triggered by skiers, snowmobiles and snow cat. At least one was remote.
  • At treeline elevations, on leeward SE-NE aspects.
  • See photos and detailed description of the remote in this MIN

Similar incidents also occurred east of Slocan in the neighboring South Columbia region, resulting in a partial burial and injury. More details and photos here. 

Small loose wet avalanches were also reported on solar aspects in the afternoon.

East of Kelowna, a natural wind slab avalanche and several explosive triggered wind slabs were reported up to size 1.5 on east through south aspects around treeline. 

On Thursday, south of Nelson, avalanche control with explosives triggered several small to large avalanches, failing below the crust that formed on Wednesday.

Snowpack Summary

A near-surface crust may make for challenging travel conditions up to 2250 m. The crust ranges from breakable to supportive and is between 1-5 cm thick. 

20-50 cm of recent storm snow sits over a variety of surfaces including a weak layer of surface hoar in wind-sheltered areas around treeline and a crust on solar aspects.

Weak layers from mid-February and late January made up of crusts and/or surface hoar crystals can be found around 60-100 cm deep. Some recent persistent slab avalanches on this layer have surprised riders, so keep this type of avalanche in mind when making terrain choices.

Terrain and Travel

  • Approach steep, open and/or sparsely treed slopes cautiously.
  • Avoid steep convexities or areas with a thin, rocky, or variable snowpack.
  • Be aware of the potential for large avalanches due to the presence of buried persistent weak layers.
  • A crust on the surface will help bind the snow together, but may make for tough travel conditions.
  • Closely monitor how the new snow is bonding to the crust.

Problems

Storm Slabs

Storm Slab avalanches are the release of a cohesive layer (a slab) of new snow that breaks within new snow or on the old snow surface. Storm-slabs typically last between a few hours and few days (following snowfall). Storm-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.