Archived

Avalanche Forecast

Apr 22nd, 2012–Apr 23rd, 2012

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

Below Threshold

The avalanche danger rating in the alpine will be below threshold

Treeline

Below Threshold

The avalanche danger rating at treeline will be below threshold

Below Treeline

Below Threshold

The avalanche danger rating below treeline will be below threshold

Alpine

Below Threshold

The avalanche danger rating in the alpine will be below threshold

Treeline

Below Threshold

The avalanche danger rating at treeline will be below threshold

Below Treeline

Below Threshold

The avalanche danger rating below treeline will be below threshold

Regions: Kootenay Boundary.

Confidence

Good

Weather Forecast

Clear skies are forecast for Monday. Ridgetop winds are expected to be light from the southwest with freezing levels reaching 3300m.

Avalanche Summary

No new avalanches have been reported from the region. This may speak more to the lack of professional observations at this time rather than actual conditions. I would expect wet natural avalanche activity on Monday resulting from forecast rising freezing levels and strong solar input.

Snowpack Summary

Recently formed windslabs have most likely settled and gained considerable strength with the warm temperatures over the weekend, and in most places transitioned into wet slabs. Below this, spring weather has left us with wet grains or melt-freeze crusts at treeline and above while warm temperatures have continued to penetrate and weaken the isothermal snowpack at lower elevations. The mid-February buried surface hoar layer is down about 140-220 cm. The likelihood of avalanches failing on this layer has been very low due to cooler temperatures, however it may wake up with warming and the consequence continues to be very large destructive avalanches. Cornices in the region are very large and have may become weak with spring temperatures.

Avalanche Problems

Loose Wet

Watch for loose wet avalanche activity on steep terrain, particularly on rocky, sun-exposed slopes. Loose wet avalanches can accelerate and entrain mass quickly.

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Very Likely - Certain

Expected Size: 1 - 5

Wet Slabs

As warm temperatures continue to penetrate the snowpack, wet slabs become more likely. Recently buried crusts and weaknesses buried deeper in the snowpack may provide suitable sliding layers for wet slabs.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Possible - Likely

Expected Size: 1 - 5

Cornices

Rising freezing levels will weaken cornices. They can be destructive by themselves and can also trigger large avalanches on the slope below.

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

Elevations: Alpine.

Likelihood: Possible - Likely

Expected Size: 1 - 5