Archived

Avalanche Forecast

Feb 12th, 2015–Feb 13th, 2015

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

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

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.

While temperatures remain unseasonably warm, treat the snowpack with an extra degree of caution.

Confidence

Fair - Due to the number of field observations

Weather Forecast

Temperatures are very warm (freezing level peaking near 2500 m) on Thursday and Friday, before cooling on Saturday with the passage of a cold front. Light precipitation is expected on Friday, followed by 5-15 mm precipitation on Saturday. This tapers to flurries on Sunday. Winds are moderate SW, changing to NW on Saturday as the front passes through.

Avalanche Summary

No new avalanches were reported on Wednesday. On Tuesday, explosives triggered a size 3 avalanche with a slab depth of 200cm. A widespread avalanche cycle occurred on Friday through Monday during the storm. Human-triggering of the persistent slab and/or wind slabs remains possible.

Snowpack Summary

Recent storm snow appears to be settling and bonding with warm temperatures. SW winds have created areas of wind slab on some alpine and treeline lee features. Keep your eyes open for cornices, which may be sensitive to collapsing with the warm temperatures. The late-Jan crust/surface hoar layer, buried up to a metre deep, remains a key concern, as triggering this would produce a surprisingly large avalanche. The mid-January surface hoar is typically down 80-120cm and is unlikely to be triggered, apart from in a thin or rocky snowpack area. The mid-December weak layer is down over 120cm, but was generally unreactive through the storm.

Avalanche Problems

Persistent Slabs

A crust buried in late January can act as a sliding surface for large avalanches. A cornice fall or small avalanche could also step down to a more deeply buried persistent weak layer.

Avoid common trigger spots, including convexities or areas with a thin or variable snowpack.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Possible

Expected Size: 3 - 6

Loose Wet

Continued warmth has weakened the snowpack, especially at low elevations. If the sun comes out, loose wet avalanches may be triggered naturally on steep sunny slopes.

Watch for terrain traps where small amounts of snow will acumulate into deep deposits.>On steep slopes, pull over periodically or cut into a new line to manage sluffing.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Likely

Expected Size: 1 - 3

Wind Slabs

Wind slabs may be lurking on lee and cross-loaded features at alpine and treeline elevations.

Avoid freshly wind loaded features.>Give cornices a wide berth when travelling on or below ridges.>

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

Elevations: Alpine, Treeline.

Likelihood: Possible

Expected Size: 1 - 3