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 5th, 2020–Feb 6th, 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 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.

Regions

Cariboos.

Wind slabs at upper elevations are the main concern. Seek out soft snow sheltered from recent winds.

Confidence

Moderate - Forecast snowfall amounts are uncertain.

Weather Forecast

Wednesday night: Cloudy, scattered snow with up to 5 cm possible, moderate northwest winds, alpine temperature -8 C.

Thursday: Cloudy, isolated flurries with trace accumulations, light southwest winds, alpine high temperature -5 C.

Friday: Partly cloudy, light south winds, alpine high temperature -6 C.

Saturday: Decreasing cloud, up to 5 cm of snow overnight, light northeast winds, alpine high temperature -6 C.  

Avalanche Summary

During the weekend storm, numerous small to very large (size 1.5-3.5) avalanches released naturally in the storm snow. These avalanches primarily occurred on leeward aspects at treeline and alpine elevations. Below tree line, wet loose avalanches were releasing naturally during the warm temperatures on Friday.

With continuous stormy weather over the past week, operators have reported several very large (size 2.5-4) avalanches breaking on deeper weak layers. Wind slab avalanches or cornice fall may have the potential to step-down to this layer.

Snowpack Summary

Ongoing snowfall since the weekend storm has totaled 20-40 cm. Human-triggered avalanches may be possible where this snow is being drifted by wind onto leeward features at upper elevations. Cornices are large and looming and may be reaching their breaking point.

40-60 cm of snow fell during the weekend storm above 1700 m. Higher snow totals fell in the southeastern parts of the region. Strong winds originating from the southwest and shifting to the northwest redistributed the snow onto lee aspects near and above treeline and accelerated cornice growth. Check out this MIN and this MIN for a helpful illustration of these conditions. During a warming event Saturday night, rain saturated snow surfaces up to around 1700 m that have since formed a crust.

The mid and lower snowpack are generally well settled and strong, however there is a weak layer of surface hoar currently buried 70 to 150 cm deep. This layer has shown signs of instability in the region on slopes between 1700-2400 m, and it may require more time to heal.

Terrain and Travel

  • Avoid freshly wind loaded features, especially near ridge crests, roll-overs and in steep terrain.
  • Seek out sheltered terrain where new snow hasn't been wind-affected.
  • Use extra caution around cornices: they are large, fragile, and can trigger slabs on slopes below.
  • 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.