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

Apr 11th, 2021–Apr 12th, 2021

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

Regions

Kootenay Boundary.

Watch for an uptick in east winds and be ready to step back if new slabs begin to form before the end of the day. Anticipate the effects of solar warming if the sun pokes out in your area.

Confidence

Moderate -

Weather Forecast

Sunday: Clear. Light northeast winds.

Monday: A mix of sun and cloud. Light to moderate east winds increasing over the day and overnight. Alpine high temperatures around -4 with freezing levels to 1600 metres. 

Tuesday: A mix of sun and cloud. Light northeast winds, increasing a bit overnight. Alpine high temperatures around -2 with freezing levels to 1800 metres. 

Wednesday: A mix of sun and cloud. Light to moderate northeast winds. Alpine high temperatures around +1 with freezing levels to 2200 metres.

Avalanche Summary

A MIN report from Saturday gives a great description of the surface instability that formed as new snow was redistributed into a reactive slab below ridgecrest in the backcountry adjacent to Big White. Similar conditions were very likely in place throughout the region. Small natural dry loose releases were also noted on southeast aspects in the Kootenay Pass area.

Looking forward, recent wind slabs may remain reactive, if a bit more stubborn, to triggering in immediately leeward terrain features, with some potential to step down to a 30 cm-deep crust layer. A forecast rise in east winds may also begin to form new slabs before the end of the day. Wet loose instabilities will again come into play in areas that see solar warming, particularly if a crust hasn't already formed.

Tuesday ushers in the start of a substantial warming trend that will begin to expand the extent of wet loose concerns to higher elevation, more shaded aspects and may eventually test deeper snowpack layers.

Snowpack Summary

A new melt freeze crust has formed on the surface on solar aspects to about 2000 metres and on all aspects up to an estimated 1500 metres. Below it, 5-15 cm of new snow through Friday night accumulated over yet another melt-freeze crust on solar aspects and otherwise added to a settled 5-20 cm of snow from last Wednesday's storm. The mid and lower snowpack are well settled and strong.

Solar warming will break down surface crusts and encourage wet loose releases -both natural and human triggered- each day on solar aspects and increasingly toward shaded alpine terrain as freezing levels march upward over the coming days.

Terrain and Travel

  • Pay attention to the wind, once it starts to blow fresh sensitive wind slabs are likely to form.
  • Carefully evaluate steep lines for wind slabs.
  • Loose avalanches may start small but they can grow and push you into dangerous terrain.
  • 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.

Loose Wet

Loose Wet avalanches are the release of wet unconsolidated snow or slush. These avalanches typically occur within layers of wet snow near the surface of the snowpack, but they may quickly gouge into lower snowpack layers. Like Loose Dry Avalanches, they start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-wet avalanches include point-release avalanches or sluffs. Loose Wet avalanches can trigger slab avalanches that break into deeper snow layers.