Archived

Avalanche Forecast

Dec 9th, 2018–Dec 10th, 2018

Alpine

2: Moderate

The avalanche danger rating in the alpine will be moderate

Treeline

1: Low

The avalanche danger rating at treeline will be low

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

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

Regions: Lizard-Flathead.

Avalanches are most likely in alpine terrain where the snow feels stiff or slabby, especially on freshly wind-loaded slopes.

Confidence

Moderate - Wind speed and direction is uncertain

Weather Forecast

SUNDAY NIGHT: Light flurries with minimal accumulations as a weak front passes overnight, moderate to strong wind out of the southwest, alpine temperatures drop to -8 C.MONDAY: Cloudy with light flurries with trace accumulations, moderate wind out of the west with strong gusts, alpine high temperatures around -4 C.TUESDAY: The next storm arrives midday, current forecasts only show about 5 cm of snow but amounts are uncertain at this point, strong wind out of the west, alpine high temperatures around -4 C.WEDNESDAY: Mix of sun and cloud with some lingering flurries, strong wind out of the west, alpine high temperatures around -2 C.

Avalanche Summary

Recent avalanche activity has been limited to a few small wind slabs and loose dry avalanches, mostly in steep alpine terrain.The last notable avalanche was a size 2 human triggered avalanche on December 2nd in Cornice Bowl north of Fernie. It occurred on a northwest facing feature at 2300 m and ran on a crust layer. There are good photos in this MIN report.

Snowpack Summary

Early season conditions prevail in this region with roughly 100 cm of snow in alpine areas and much less at lower elevations. Surface conditions range from soft power, to hard wind slab, and some sun crusts.See the snow profile in our field team's MIN report for a visual representation of the snowpack here. The main concern is a combination of weak facets and crusts in the bottom half of the snowpack. The crust is most prevalent at and above treeline and is likely most problematic on north-facing features, especially those that are large and planar in nature. A layer of large surface hoar can also be found at similar depths in some areas, as found in a recent MIN report here.

Avalanche Problems

Wind Slabs

Strong wind will transport loose snow and potentially form reactive slabs in the alpine. Wind slabs have the potential for wide propagations if they step down to the weak snow in the lower snowpack.

Use ridges or ribs to avoid pockets of wind loaded snow.Be alert to conditions that change with elevation, aspect and exposure to wind.If triggered the wind slabs may step down to deeper layers resulting in large avalanches.

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

Elevations: Alpine.

Likelihood: Possible

Expected Size: 1 - 2