Archived

Avalanche Forecast

Dec 5th, 2017–Dec 6th, 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

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

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.

One more day of cool weather before alpine temperatures soar. Watch for wind slabs on Wednesday and avoid slopes getting hit by the sun.

Confidence

Moderate - Due to the number and quality of field observations

Weather Forecast

WEDNESDAY: Sunny with valley cloud in the morning, light northwest wind, inversion forming with alpine temperatures reaching -4 C.THURSDAY: Sunny with valley cloud, light wind, inversion with freezing level up to 3000 m.FRIDAY: Sunny with valley cloud, light wind, inversion with freezing level up to 2700 m.

Avalanche Summary

Limited reports from the region over the past few days show a pattern of touchy wind slabs around alpine ridges. On Tuesday, a size 1.5 wind slab was triggered by a skier on a south-facing slope at 2600 m in the Invermere area. A Mountain Information Network (MIN) report describes multiple size 1 wind slabs triggered by ski cutting from the Golden area 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

Fresh wind slabs have been forming throughout the week, so be careful around ridges and gullies. Solar warming may make slabs extra reactive on south-facing slopes.

Travel on ridgetops to avoid wind slabs on slopes below.Be careful with wind loaded pockets, especially near ridge crests and roll-overs.Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet.

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

Elevations: Alpine, Treeline.

Likelihood: Possible

Expected Size: 1 - 2