Archived

Avalanche Forecast

Dec 27th, 2019–Dec 28th, 2019

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

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

2: Moderate

The avalanche danger rating below treeline will be moderate

Regions: Northwest Inland.

Triggering avalanches is most likely in steep terrain at higher elevations where new snow and wind is forming unstable slabs.

Confidence

Moderate - Uncertainties in both the snowpack structure and the weather forecast limit our confidence.

Weather Forecast

FRIDAY NIGHT: 5-15 cm of snow overnight, 40-60 km/h wind from the southwest, alpine temperatures around -3 C.

SATURDAY: Scattered flurries bring another 5-20 cm of snow above 1000 m, 40-70 km/h wind from the southwest, alpine high temperatures around -3 C.

SUNDAY: Mostly cloudy with isolated flurries, 20-30 km/h wind from the south, alpine high temperatures around -5 C.

MONDAY: Next frontal system arrives bringing 5-15 cm of snow by the afternoon, 50-80 km/h wind from the southwest, alpine high temperatures around -3 C.

Avalanche Summary

No recent avalanches have been reported.

Snowpack Summary

10-30 cm of new snow and strong wind could form reactive slabs at upper elevations on Saturday. Currently, sheltered terrain has 20-30 cm of low density snow while exposed terrain has been affected by recent wind from the south and southwest. Reports suggest there are two buried layers of surface hoar in the upper snowpack, both 25-50 cm below the surface. In windward terrain the snow may be scoured down to a hard crust from November. In leeward terrain, this crust is 40-80 cm deep. Older crusts can be found deeper in the snowpack and are generally breaking down. In areas with a relatively thin snowpack, the base of the snowpack likely consists of weak faceted grains.

Terrain and Travel

Storm snow and wind is forming touchy slabs. Use caution in lee areas in the alpine and treeline.
Dial back your terrain choices if you are seeing more than 25cm of new snow.
If you are increasing your exposure to avalanche terrain, do it gradually as you gather information.

Avalanche Problems

Wind Slabs

Moderate amounts of new snow and strong wind will form unstable slabs in steep terrain at higher elevations, especially around ridges and convex rolls.

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

Elevations: Alpine, Treeline.

Likelihood: Likely

Expected Size: 1 - 2