Archived

Avalanche Forecast

Dec 19th, 2017–Dec 20th, 2017

Alpine

4: High

The avalanche danger rating in the alpine will be high

Treeline

4: High

The avalanche danger rating at treeline will be high

Below Treeline

4: High

The avalanche danger rating below treeline will be high

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

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

2: Moderate

The avalanche danger rating below treeline will be moderate

Regions: Lizard-Flathead.

A significant storm is expected to raise avalanche danger to high for Wednesday.

Confidence

Moderate - Intensity of incoming weather systems is uncertain on Wednesday

Weather Forecast

Tonight: 10-20 cm new snow expected. Moderate easterly winds.Wednesday: a further 10-20 cm new snow expected. Moderate northeasterly winds. Treeline temperatures around -8C.Thursday: Mostly dry during the day. Moderate northwesterly winds. Treeline temperatures around -10C.Friday: Light snow, 2-5 cm. Light easterly winds. Treeline temperatures around -12C.

Avalanche Summary

On Monday, a natural and explosive triggered avalanche cycle was reported in the Lizard Range up to size 2.5 or 3. On Tuesday, smaller (size 1.5) avalanches were readily triggered by ski cutting and explosive avalanche control.

Snowpack Summary

50-60 cm new snow now rests on a variety of old surfaces. These old surfaces include crusts on south through west facing slopes, wind-scoured slopes and, in sheltered terrain at and below treeline, large feathery surface hoar crystals. Lower in the snowpack, you should be able to find a hard crust that was buried near the end of November. This crust is approximately 30cm thick and extends from 1600m to mountain top on all aspects. Average snowpack depths at treeline in the region range from 90 to 130cm.

Avalanche Problems

Storm Slabs

Storm snow totals of 100 cm are likely by Wednesday. Avalanches could be large and run further than expected. It's a good time to throttle back more than you think is required and minimize exposure to overhead hazard as well as the terrain you're on.

Avoid all avalanche terrain during periods of heavy loading from new snow, wind, or rain.

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Very Likely

Expected Size: 1 - 3