Archived

Avalanche Forecast

Jan 20th, 2019–Jan 21st, 2019

Alpine

3: Considerable

The avalanche danger rating in the alpine will be considerable

Treeline

2: Moderate

The avalanche danger rating at treeline will be moderate

Below Treeline

1: Low

The avalanche danger rating below treeline will be low

Alpine

2: Moderate

The avalanche danger rating in the alpine will be moderate

Treeline

2: Moderate

The avalanche danger rating at treeline will be moderate

Below Treeline

1: Low

The avalanche danger rating below treeline will be low

Alpine

3: Considerable

The avalanche danger rating in the alpine will be considerable

Treeline

2: Moderate

The avalanche danger rating at treeline will be moderate

Below Treeline

2: Moderate

The avalanche danger rating below treeline will be moderate

Regions: South Coast Inland.

The recent snow may not be bonding well to underlying layers, with many reports of small avalanches in wind-affected terrain. Travel conservatively, particularly if you notice snow with slab properties or see signs of instability.

Confidence

High -

Weather Forecast

SUNDAY NIGHT: Clear skies, freezing level below valley bottom.MONDAY: Mostly clear skies, light northwest winds, alpine temperature -9 C, freezing level below valley bottom.TUESDAY: Mostly cloudy, light to moderate southwest winds, alpine temperature -5 C, freezing level rising to 1200 m.WEDNESDAY: Cloudy with light snowfall, accumulation 5 to 15 cm, moderate southwest winds, alpine temperature -4 C, freezing level 1200 m.

Avalanche Summary

Numerous small to large (size 1 to 2) wind slabs were easily triggered by skiers near ridges on Saturday (for example see here). The snow was failing within the recent storm snow, 20 to 30 cm deep. One of these avalanches stepped down to a deeper layer (see link in Snowpack Summary).

Snowpack Summary

Around 20 to 40 cm of snow recently fell in the region with the most around Coquihalla. The snow fell with associated strong southwest winds, which has produced wind affected snow surfaces in expose terrain. This recent snow fell onto a sun crust on southerly aspects, a temperature crust below around 1700 m on all aspects, and feathery surface hoar in areas sheltered by the wind at all elevation bands. The new snow may not bond well to these layers.Below this, the snowpack is generally well-settled. In certain parts of the region, you may still find a weak layer of surface hoar buried about 60 to 100 cm in sheltered areas around treeline. This layer was recently triggered by a skier in the north of the region (see here). In the south of the region, snowpack tests suggest that avalanches could still be triggered within the layer (see here).

Avalanche Problems

Wind Slabs

The recent snow may not bond well to underlying layers. The touchiest snow may be in exposed terrain, as the snow fell with strong winds. There is potential for triggered avalanches to step-down to deeper weak layers and produce larger avalanches.

Observe for the bond of the new snow to underlying surfaces.Watch for signs of instability such as whumpfing, cracking, or recent avalanches.Use caution in lee areas. Recent wind loading has created wind slabs.

Aspects: North, North East, East, South East, West, North West.

Elevations: All elevations.

Likelihood: Possible - Likely

Expected Size: 1 - 2