Archived

Avalanche Forecast

Mar 28th, 2016–Mar 29th, 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

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

2: Moderate

The avalanche danger rating below treeline will be moderate

Regions: Kootenay Boundary.

Solar warming will drive the Avalanche Danger throughout the forecast period. Watch your overhead hazard and be alert to conditions that change with aspect, elevation and time of day.

Confidence

High

Weather Forecast

A ridge of high pressure will dominate the province bringing mainly clear skies and generally light ridgetop winds for the forecast period. The freezing level will rising gradually from about 2000m on Tuesday to about 2900m by Thursday.

Avalanche Summary

On Sunday, small storm slabs (in the size 1 range) were reported at higher elevations in the Rossland area. No other avalanches were reported. A new round of storm slab activity is expected in response to new snow and moderate winds on Sunday. Storm slab activity may persist for longer than usual due to underlying surface hoar. With forecast sunny weather, widespread loose wet avalanche activity can also be expected, especially in steep, sun-exposed terrain. Warming may also trigger cornice falls which could, in turn, trigger destructive persistent weaknesses.

Snowpack Summary

13-25cm of new snow overlies small surface hoar on shaded slopes and a melt-freeze crust on sun-exposed slopes. About 30-50cm below the surface, you'll likely find another hard crust which exists everywhere except high, north-facing terrain. The late February persistent weak layer down 70 to 120 cm remains a low probability / high consequence concern. Test results are variable, with occasional sudden planar (pop) results. While generally becoming unlikely to trigger, this layer could wake up with a cornice fall, warm temperatures or from a thin snowpack area. Cornices are large and looming and will become weak with forecast warming and solar radiation

Avalanche Problems

Loose Wet

Watch for pushy loose wet avalanches at all elevations throughout the forecast period. The combination of new snow, buried crusts and solar radiation will make conditions extra touchy on sun-exposed slopes.

Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet.>Avoid exposure to terrain traps where the consequences of a small avalanche could be serious.>Avoid exposure to solar aspects overhead, large avalanches may reach the end of run out zones.>

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

Elevations: All elevations.

Likelihood: Likely - Very Likely

Expected Size: 1 - 3

Cornices

Large fragile cornices threaten many slopes and will become increasingly touchy with solar radiation. A cornice fall could be the large trigger required to awaken destructive buried weak layers.

Do not travel on slopes that are exposed to cornices overhead.>Give cornices a wide berth when travelling on or below ridges.>Cornices become weak with daytime heating, so travel early on exposed slopes.>

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

Elevations: Alpine, Treeline.

Likelihood: Possible - Likely

Expected Size: 1 - 4

Storm Slabs

Snow and wind on Sunday night have formed new storm slabs which should be touchiest in higher elevation, wind-exposed terrain. Storm slabs may remain reactive due to underlying surface hoar.

Stay off recent wind loaded areas until the slope has had a chance to stabilize.>Be cautious as you transition into wind affected terrain.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Possible - Likely

Expected Size: 1 - 3