Avalanche Forecast

Archived

Jan 19th, 2022–Jan 20th, 2022

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Regions

South Coast Inland.

Touchy new wind slabs are expected on Thursday throughout the region.

There is uncertainty about the track and intensity of the storm, and areas around the Coquihalla may see more snowfall than the rest of the region. With more than around 25 cm new, treat the danger as HIGH.

Confidence

Moderate - Uncertainty is due to the timing, track, & intensity of the incoming weather system.

Weather Forecast

A storm system impacts to the coast Wednesday night and Thursday before a warm ridge of high pressure establishes on Friday.

Wednesday Night: Snowfall 5-10 cm, wind becoming strong SW, freezing levels 1200-1400 m.

Thursday: Snowfall 10-15 cm, strong SW wind, freezing levels reaching around 1500 m.

Friday: A mix of sun and cloud, light to moderate NW wind, freezing levels climbing to around 3000 m with an inversion.

Saturday: Mainly sunny, light NW wind, freezing levels around 3000 m with an inversion.

Avalanche Summary

On Tuesday, a ski cut triggered a size 1 wind slab on a NE aspect at 1950 m in the north of the region failing down 30 cm on a crust. A size 1.5 wind slab was also remotely triggered from a ridge on a NW aspect at 1950 m.

Snowpack Summary

The new snow continues to bury a widespread crust which extends into alpine elevations. There have also been reports of a layer of small surface hoar above this crust in the north of the region. Reactive wind slabs have been reported recently and new wind slabs will continue to develop during the storm on Thursday.

The early December crust/facet layer is now typically down 100-150 cm but may be as shallow as 60 cm and as deep as 200 cm with lots of variability through the region. The layer is most prominent between 1700 and 2100 m. The crust appears to be breaking down in the south of the region but remains a concern in the north. The layer has been dormant recently but is a concern for the period of major warming and sun forecast for the weekend. The most likely place to trigger it would be in thin, rocky snowpack areas where it is shallowest.

Terrain and Travel

Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
Be alert to conditions that change with elevation and wind exposure.
The more the snow feels like a slurpy, the more likely loose wet avalanches will become.

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.