Archived

Avalanche Forecast

Apr 4th, 2016–Apr 5th, 2016

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

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

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: Kootenay Boundary.

If the sun peeks out, a round of natural avalanches may occur.

Confidence

Moderate - Timing or intensity of solar radiation is uncertain on Tuesday

Weather Forecast

Cloud, moderate to strong NW winds and a few snow showers may linger on Tuesday morning, before a ridge brings dry and very warm weather again for the remainder of the week. Freezing levels are expected to climb above 3000 m by Wednesday.

Avalanche Summary

A natural cycle of size 1-2 loose wet avalanches continued though the week and into Saturday. On Friday, an explosives control mission near Nelson produced several size 2-3 wet slab avalanches. A size 3 cornice-triggered slab also released naturally.

Snowpack Summary

Large cornices overhang alpine slopes and threaten to trigger avalanches on slopes below. New snow will have landed on moist or crusty snow surfaces, and may have been shifted by strong winds into wind slabs. At low elevations, the snowpack is isothermal. The late February surface hoar/ crust interface (down 80 to 130 cm) remains a low probability/ high consequence concern. While generally unlikely to be triggered, this layer could produce surprisingly large avalanches with a cornice fall or warm temperatures.

Avalanche Problems

Wind Slabs

Snow may have been shifted by strong winds into wind slabs at high elevations.

Be cautious as you transition into wind affected terrain.>Choose well supported terrain without convexities.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Possible - Likely

Expected Size: 1 - 3

Cornices

Large fragile cornices threaten many slopes. A cornice fall could trigger a large avalanche on the slope below.

Do not travel on slopes that are exposed to cornices overhead.>Give cornices a wide berth when travelling on ridges.>

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

Elevations: Alpine, Treeline.

Likelihood: Possible

Expected Size: 1 - 5

Loose Wet

If the sun peeks out, loose wet avalanches are possible on steep, sunny terrain.

Avoid exposure to terrain traps where the consequences of a small avalanche could be serious.>Minimize exposure to sun exposed slopes when the solar radiation is strong.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Possible

Expected Size: 1 - 3