Archived

Avalanche Forecast

Dec 27th, 2016–Dec 28th, 2016

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

Alpine

3: Considerable

The avalanche danger rating in the alpine will be considerable

Treeline

3: Considerable

The avalanche danger rating at treeline will be considerable

Below Treeline

3: Considerable

The avalanche danger rating below treeline will be considerable

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: Sea To Sky.

Watch for signs of recent wind loading in exposed terrain. Wind slabs are expected to be reactive to human triggering on Wednesday.

Confidence

Moderate - Intensity of incoming weather systems is uncertain on Thursday

Weather Forecast

Unsettled conditions are expected for Wednesday with the potential for both light flurries and sunny breaks. Alpine wind is forecast to be moderate from the west to northwest direction and freezing levels are expected to reach around 800 m. The next storm front is forecast to arrive Wednesday overnight. 20-30cm of new snowfall is forecast by Thursday evening. Alpine wind is forecast to be strong from the southwest and freezing levels are forecast to reach around 1000 m. Friday is currently forecast to be dry and sunny.

Avalanche Summary

On Tuesday, explosives and ski cutting produced soft slab avalanches up to size 1.5 which were confined to the new storm snow. On Wednesday, wind slabs are expected to be the main concern. Ongoing strong southerly winds are redistributing the 20-30 cm of new snow from Tuesday.

Snowpack Summary

20-30 cm of new snow has accumulated since Monday. This new snow sits over a variable interface which consists of wind affected surfaces, faceted (sugary) snow, or surface hoar. The surface hoar has been observed up to 20 mm in size in the Whistler area and it is reported to exist at and below treeline. Recently strong southerly winds have formed new wind slabs in leeward and cross loaded features in wind exposed terrain.

Avalanche Problems

Wind Slabs

New wind slabs are expected to be reactive to human triggering on Wednesday. Ongoing strong southerly winds have been loading leeward and cross loaded terrain features in wind exposed terrain.

Use ridges or ribs to avoid pockets of wind loaded snow.Avoid terrain where the surface snow feels stiff or slabby.Use caution in lee areas. Recent wind loading has created wind slabs.

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

Elevations: Alpine, Treeline.

Likelihood: Possible - Likely

Expected Size: 1 - 2