Archived

Avalanche Forecast

Dec 17th, 2015–Dec 18th, 2015

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

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

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: Glacier.

Watch for the shallow, weak areas in the snowpack. There is still significant variability in snow depths.

Weather Forecast

A cold, clear day in Rogers Pass today. Winds will remain light NW. Into the evening and tomorrow, a frontal system tracks across the region, bringing 10-15cm of snow by Friday night. SW winds will spike mid-day to strong, with freezing levels rising to 1000m.

Snowpack Summary

20-30cm of snow covers a supportive crust below 1600m. 20-80cm of settled snow covers the Dec 2 interface, which is surface hoar below tree-line and a sun crust on steep, solar tree-line and alpine features. The depth is variable due to wind-scouring. At shallow depths, it is still reactive in snowpack tests in the moderate to hard range.

Avalanche Summary

Sluffing and skier triggered size 1's from sidewalls of steep gully features have been reported in the alpine. Yesterday, a team was able to ski cut small size 1's from steep, unsupported features at and below tree-line in NRC Gully. These soft slabs were failing on the Dec 2 surface hoar/sun crust, which was only 20cm deep due to wind-scouring.

Confidence

Intensity of incoming weather systems is uncertain

Avalanche Problems

Persistent Slabs

Varying depths of settled snow sits on top of the Dec 2 persistent weak layer, which is surface hoar at and below tree line and sun crust on solar aspects tree line to alpine. The layer has produced moderate-hard results in field tests.

Be careful with wind loaded pockets, especially near ridge crests and roll-overs.Avoid shallow snowpack areas where triggering is more likely.

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Possible

Expected Size: 1 - 3