Archived

Avalanche Forecast

Dec 11th, 2014–Dec 12th, 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

2: Moderate

The avalanche danger rating below treeline will be moderate

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

Regions: Cariboos.

Although the trend shows improvement remember that the potential for triggering an avalanche is greatest at higher elevations due to recent heavy snowfall and strong winds.

Confidence

Fair - Due to the number of field observations

Weather Forecast

One last system is expected to cross the province tonight bringing moderate precipitation, high winds, and maintaining high freezing levels. We could see 10-20 cm on Friday. Freezing levels start near 1800 m but should drop to 1500 m late in the day. Winds are strong from the South-Southwest easing to light from the Northwest. The weekend looks much drier with a mix of sun and cloud. Freezing levels around 800-1000 m on Saturday and valley bottom on Sunday. Winds remain light.

Avalanche Summary

A widespread natural avalanche cycle with slides up to size 3.5 was reported south of Valemount on Thursday. Large slab avalanches were observed above 2000 m and numerous wet slides were observed at lower elevations in steep terrain. Similar activity was likely in other parts of the region.

Snowpack Summary

The storm snow is expected to be wet up to around 2000 m and moist up to around 2400 m. Below the old storm snow (15-30cm) is a weak layer of surface hoar. Reports from the region suggest that anywhere from 50-150 cm of settling snow overlies one or more weak layers which formed during November. Snowpack tests suggest that these weak layers are getting harder to trigger but still have the potential to produce large avalanches if triggered. Recent strong winds and warm temperatures have likely created deep and dense wind slabs in lee features in exposed alpine terrain.

Avalanche Problems

Storm Slabs

Storm and wind slabs continue to build, primarily above 1800 m. Very strong winds may have created deep wind slabs well below ridge crests and cross-loaded gullies.

Use ridges or ribs to avoid freshly wind loaded features. >Choose well supported terrain without convexities.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Likely

Expected Size: 1 - 4

Persistent Slabs

The likelihood of triggering a persistent slab should decrease heading into the weekend but be very wary of any slope that did not release or may have been reloaded during the latest storm cycle.

Avoid common trigger zones including thin snowpack areas, near rocky outcrops, and steep alpine slopes.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Unlikely - Possible

Expected Size: 2 - 6

Loose Wet

Loose wet avalanches should become less likely as conditions dry and cool heading into the weekend.

Be cautious of sluffing in steep terrain.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Possible

Expected Size: 1 - 2