Archived

Avalanche Forecast

Dec 4th, 2017–Dec 5th, 2017

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

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

Regions: Purcells.

Fresh wind slabs are likely at higher elevations. Evaluate the snow and terrain carefully as there is still limited information from this region.

Confidence

Moderate - Due to the number and quality of field observations

Weather Forecast

TUESDAY: Alpine sun and valley cloud, light wind, alpine temperatures around -7 C.WEDNESDAY: Sunny with valley cloud, light wind, inversion forming with alpine temperatures possibly reaching above 0 C.THURSDAY: Sunny with valley cloud, light wind, inversion with freezing level up to 3000 m.

Avalanche Summary

A Mountain Information Network (MIN) report from the Golden area describes multiple size 1 wind slabs produced by ski cutting on Sunday. Several size 1 wind slabs were also triggered by explosives near ridge crests throughout the region over the weekend.

Snowpack Summary

Snow from last week's storms is settling and getting redistributed into fresh wind slabs by northwest winds. Roughly 20-40 cm of recent snow sits above various crusts from the warm weather in late November. Two deeper layers may be found in the snowpack, including the November 10 surface hoar and the Halloween crust (80 to 100 cm deep). The late November crust is the most likely of these layers to develop into a problem in the future. Snow depths decrease rapidly below treeline, where the primary hazards are rocks, stumps, and open creeks.

Avalanche Problems

Wind Slabs

Wind slabs are most likely on the downwind side of ridges and gullies. Changes in wind direction may form fresh wind slabs this week.

Be careful with wind loaded pockets, especially near ridge crests and roll-overs.Travel on ridgetops to avoid wind slabs on slopes below.

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

Elevations: Alpine, Treeline.

Likelihood: Possible

Expected Size: 1 - 2