Archived

Avalanche Forecast

Dec 22nd, 2014–Dec 23rd, 2014

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

3: Considerable

The avalanche danger rating below treeline will be considerable

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

3: Considerable

The avalanche danger rating below treeline will be considerable

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: South Columbia.

It's easy to trigger avalanches right now. Conditions are expected to deteriorate further before Christmas. Play safe.

Confidence

Fair - Forecast snowfall amounts are uncertain

Weather Forecast

Expect moderate snowfall on Tuesday (10-25cm) with moderate to strong south-westerly winds and freezing level around 500m. A cooler northwest flow should bring light snow or flurries on Wednesday and Thursday.

Avalanche Summary

Numerous storm slabs up to size 2.5 were triggered naturally, by skiers (including remote skier triggering) and by explosives on Sunday. Many were on lee east- to north-facing slopes, but there were some reports from all aspects at treeline and above.

Snowpack Summary

Anywhere from 20-90 cm of storm snow has built up and been shifted by winds, creating slabs above a touchy layer of large surface hoar crystals. Below around 2100m, this surface hoar sits on a hard rain crust. Above 2100m the surface hoar sits on well settled and faceted snow. This interface is highly reactive (see avalanche summary). A thick rain crust with facets from early November is buried over 1 m down and may still be reactive in isolated areas.

Avalanche Problems

Storm Slabs

Slab avalanches have been failing easily with the weight of a person, or even from a distance. Storm snow has built up over a touchy layer of buried surface hoar crystals.

Choose well supported terrain without convexities.>Avoid freshly wind loaded features by sticking to ridges and ribs.>Remote triggering is possible, so give suspect avalanche terrain a wide berth.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Likely

Expected Size: 1 - 4

Deep Persistent Slabs

There is still the potential to trigger a deeply buried weak layer, resulting in a surprisingly large avalanche.

Avoid shallow snowpack areas where triggering is more likely.>

Aspects: All aspects.

Elevations: Alpine.

Likelihood: Unlikely - Possible

Expected Size: 3 - 6