Archived

Avalanche Forecast

Feb 12th, 2015–Feb 13th, 2015

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

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

1: Low

The avalanche danger rating below treeline will be low

Regions: Kootenay Boundary.

Warm temperatures and sunny breaks are on the menu for Friday. Use caution in steep open terrain and around large overhanging cornices.

Confidence

Fair

Weather Forecast

Friday: Cloudy with sunny breaks. The freezing level is between 2500-3000 m. Ridge winds are light to moderate from the west. Saturday: Cloudy with possible light snow. The freezing level lowers to around 1800-2000 m. Winds are generally light from the W-NW. Sunday: Cloudy with light snow and occasional sunny breaks. The freezing level is around 1400-1500 m.

Avalanche Summary

Only one size 1 skier controlled avalanche on a steep convex roll was reported on Wednesday. Reports from Tuesday include evidence of old natural slab avalanches up to Size 2.5. Heavy triggers such as explosives and snowcats were able to trigger 20-90 cm deep storm slabs up to Size 2, but no new naturals were observed and ski-cutting was ineffective.

Snowpack Summary

The rain line during recent heavy precipitation generally hovered around 1700m, although there were periods where rain fell into the alpine. Above that elevation, heavy accumulations of moist, dense snow have been pushed by strong southwest winds into cornices and deeper deposits on the lee side of ridgecrests and terrain breaks. Recent storm snow is poorly bonded to a hard crust, which may have overlying surface hoar, that was buried late January. The mid-December crust/facet/surface hoar weakness may be persisting in the mid to lower snowpack at higher elevations.

Avalanche Problems

Persistent Slabs

A couple of notable persistent weak layers, buried 60-120 cm deep, remain a concern for human triggering, especially in the alpine.

Be aware of the potential for large, deep avalanches due to the presence of buried surface hoar.>Be aware of thin areas that may propagate to deeper instabilities.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Possible

Expected Size: 3 - 6

Loose Wet

Loose wet and wet slab avalanches remain a concern at lower elevations where rain has saturated the snowpack.

Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet.>Be cautious of sluffing in steep terrain.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Possible - Likely

Expected Size: 1 - 3