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

Jan 16th, 2020–Jan 17th, 2020

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

Regions

Northwest Inland.

If you decide to brave the cold Friday, low elevation trees are your best chance at avoiding windslabs and finding soft snow. The short trip from the car is an added bonus on a chilly day.

Confidence

Moderate - Uncertainty is due to the limited number of field observations.

Weather Forecast

Thursday night: Few clouds with isolated flurries bringing a trace of new snow. Light south winds. Alpine temperatures around -28 C.

Friday: Mix of sun and cloud. Light south to southwest winds. Alpine temperatures around -26 C.

Saturday: Mix of sun and cloud with isolated flurries bringing up to 5 cm of new snow. Strong southeast to southwest winds. Alpine temperatures around -18 C.

Sunday: Mix of sun and cloud with isolated flurries bringing up to 5 cm of new snow. Moderate southeast to southwest winds, strong at ridgetop. Alpine temperatures around -15 C.

Avalanche Summary

On Wednesday, we received reports of skier triggered windslab avalanches size 1.5-2.5 around treeline. Crown depths were around 1 m, and they ran on a surface hoar layer buried by the previous storm on January 10th. 

Reports from the Bulkley Valley Monday detail natural windslab and persistent slab avalanche activity, size 2.5-3 on aspects lee to previous strong outflow winds. The persistent slab avalanches are suspected to be isolated incidents of avalanches running on the deep November crust.

Snowpack Summary

North to east aspects in the alpine have been wind scoured, with isolated hard windslab in lees. Wind effect also observed in open areas at treeline and below, where wind loaded pockets have been observed to exceed 1 m in depth. Snow in protected areas is unconsolidated and well preserved by the cold temperatures. 

Recent reports indicate that this wind affected surface snow overlies a layer of surface hoar in many areas, particularly at treeline. This layer has been associated with recent skier triggered avalanche activity. Deeper in the snowpack, another couple of surface hoar layers are currently buried about 80-120 cm below the surface in sheltered areas around treeline. There have been no reports of avalanche activity associated with them for a few weeks, during which several storm slab avalanche cycles have tested their potential for step-downs.

A deep crust from mid November lurks at the base of the snowpack. A couple of recent large avalanches are suspected to have run on this layer in isolated incidents high in the alpine.

Terrain and Travel

  • Sheltered low elevation terrain will likely offer the best and safest riding today.
  • Be careful with wind slabs, especially in steep, unsupported and/or convex terrain features.
  • Be aware of the potential for surprisingly large avalanches due to deeply buried weak layers.
  • Avoid thin areas like rock outcroppings where you're most likely to trigger avalanches failing on deep weak layers.

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.

Deep Persistent Slabs

Deep Persistent Slab avalanches are the release of a thick cohesive layer of hard snow (a slab), when the bond breaks between the slab and an underlying persistent weak layer deep in the snowpack. The most common persistent weak layers involved in deep, persistent slabs are depth hoar or facets surrounding a deeply buried crust. Deep Persistent Slabs are typically hard to trigger, are very destructive and dangerous due to the large mass of snow involved, and can persist for months once developed. They are often triggered from areas where the snow is shallow and weak, and are particularly difficult to forecast for and manage.