Archived

Avalanche Forecast

Apr 9th, 2013–Apr 10th, 2013

Alpine

4: High

The avalanche danger rating in the alpine will be high

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

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.

Confidence

Fair - Intensity of incoming weather is uncertain on Wednesday

Weather Forecast

Wednesday: Moderate to locally heavy snowfall starting Tuesday night and continuing Wednesday / Moderate northwest winds / Freezing level at 1500mThursday: Light snowfall / Moderate northwest winds / Freezing level at 1200m Friday: Light snowfall intensifying throughout the afternoon / Light south winds / Freezing level at 1000m

Avalanche Summary

On Monday a couple of slab avalanche to size 2.5 were remotely triggered by a skier from 300m away. The avalanches occurred on a northwest aspect in the high alpine. The early April surface hoar/ facet interface is though to be the culprit.

Snowpack Summary

At upper elevations 20-45cm of recent snow is covering a crust or moist snow. At the same interface you may find a touchy layer of facets or surface hoar on shaded high alpine slopes. Where they exist, these weak crystals have been responsible for large remote triggers. The variable and reactive nature of this layer suggests that it may continue to catch people by surprise. I'd dig down and test for this weakness before committing to any exposed alpine terrain.At lower elevations (below 1700m) rain has made the snow surface wet or moist. Recent snowfall combined with wind have made large cornices even bigger.

Avalanche Problems

Storm Slabs

Steady snowfall on Wednesday will add to an existing storm/ wind slab problem. Storm slabs may be particularly touchy in wind-affected terrain, or in spots where they overlie weak and reactive surface hoar crystals.

Stay off recent wind loaded areas until the slope has had a chance to stabilize.>Be aware of the potential for large avalanches due to the presence of buried surface hoar.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Very Likely

Expected Size: 1 - 5

Loose Wet

Rain at lower elevations will promote ongoing wet snow instabilities. Watch for loose wet avalanches on steep slopes, or glide cracks in terrain with smooth ground cover.

Watch for wet loose or slab activity with forecast rain and/or warm temperatures.>

Aspects: All aspects.

Elevations: Alpine.

Likelihood: Possible - Likely

Expected Size: 1 - 4