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, 2020–Mar 7th, 2020

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

Regions

Cariboos.

Recent snow and wind have formed reactive wind slabs at upper elevations that remain possible to human trigger. A buried weak layer warrants a conservative mindset and terrain use strategy, particularly in the south of the region. 

Confidence

Moderate - Uncertainty is due to field data and reports showing a wide variation in conditions throughout the region.

Weather Forecast

Friday night: Mostly clear, light variable winds, alpine temperature -12 C.

Saturday: Partly cloudy, isolated flurries with trace accumulations, light variable winds, alpine high temperature -7 C, freezing level at valley bottom.

Sunday: Mostly clear, light southwest winds, alpine high temperature -7 C, freezing level at valley bottom.

Monday: Mostly clear, light southwest winds, alpine high temperature -5 C, freezing level 1000 m.

Avalanche Summary

On Wednesday and Thursday, a natural cycle of large to very large (size 2-3) avalanches released in the recent storm snow, primarily on wind-loaded aspects (northeast, east, and southeast) above 1800 m. Several were triggered by large cornices failures. 

Over the past week, there have been many reports of persistent slab avalanches releasing on the Feb 22 surface hoar. These avalanches primarily occurred on north, northeast, and east aspects between 1400-2100 m. Check out this MIN for a helpful illustration of where you might expect to find this problem. 

Snowpack Summary

Incremental snowfall and strong winds continue to build wind slabs in the alpine and open areas at treeline. A few sun crusts exist on solar aspects in the upper snowpack. Convective snowfall in the wake of the storm may obscure the evidence of these wind slabs.

A weak layer of surface hoar may be found 60-100 cm deep. There is uncertainty about the distribution and reactivity of this layer, especially in the north of the region. Sheltered slopes near treeline are most suspect. Read more about surface hoar on our forecaster blog! 

Below a melt-freeze crust down 80-120 cm from early February, the snowpack is well settled and strong.

Terrain and Travel

  • Stay off recently wind loaded slopes until they have had a chance to stabilize.
  • Be aware of the potential for large avalanches due to the presence of buried surface hoar.
  • Use conservative route selection and resist venturing out into complex terrain.
  • Even brief periods of direct sun could produce natural 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.