Archived

Avalanche Forecast

Mar 26th, 2016–Mar 27th, 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

2: Moderate

The avalanche danger rating in the alpine will be moderate

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

2: Moderate

The avalanche danger rating in the alpine will be moderate

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.

Forecast snowfall amounts for Sunday vary greatly across the region. Pay close attention to how much snow falls in your riding area, and watch for conditions that change throughout the day.

Confidence

Moderate - Intensity of incoming weather systems is uncertain on Sunday

Weather Forecast

Between 10-20cm of new snow is expected to fall throughout the day on Sunday. Winds associated with the system should be generally moderate from the west. A dry ridge of high pressure will bring increasingly clear skies and light northerly winds for Monday and Tuesday. Freezing levels should sit at about 1400m on Sunday, and the climb to about 1800m on Monday and Tuesday.

Avalanche Summary

In recent days a handful of size 1-2 storm slabs were triggered by skiers, naturally and with explosives. These were almost all on NW-NE aspects and above 1900 m. New snow and moderate winds on Sunday will likely promote further storm slab activity.

Snowpack Summary

Cornices are large and looming in some areas. Recently formed melt freeze/ sun crusts are now buried by storm slabs and variable wind slabs. Several crusts are buried in the upper snowpack. The late February persistent weak layer down 70 to 120 cm remains a lingering concern. Test results are variable, with occasional sudden planar (pop) results. This interface may remain more reactive on northerly (shaded) aspects above about 1700 m, where buried surface hoar has the best chance of preservation. On sunny aspects, this interface may be a crust/ facet layer. While becoming unlikely, it could be triggered by a cornice fall or from a thin snowpack area.

Avalanche Problems

Storm Slabs

Snow and wind on Sunday will form new storm slabs which should be touchiest in higher elevation, wind-exposed terrain. New storm slabs should increase with size and reactivity throughout the day.

Choose well supported terrain without convexities.>Be cautious as you transition into wind affected terrain.>Be alert to conditions that change throughout the day.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Likely

Expected Size: 1 - 3

Cornices

Large fragile cornices threaten many slopes. A cornice fall could be the large trigger required to awaken deeper weak layers.

Do not travel on slopes that are exposed to cornices overhead.>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 - 4