Avalanche Forecast

Issued: Apr 17th, 2018 4:18PM

The alpine rating is considerable, the treeline rating is considerable, and the below treeline rating is considerable. Known problems include Loose Wet and Storm Slabs.

mconlan, Avalanche Canada

Kootenay Boundary.

Sun and warming will increase the likelihood of avalanches. Both loose wet and storm slab avalanches could be triggered naturally or by humans. Be particularly cautious on south slopes when it is sunny and avoid overhead exposure.

Summary

Confidence

Moderate - Due to the number of field observations

Weather Forecast

WEDNESDAY: Sunny with afternoon clouds, light southeast winds, alpine temperature -3 C, freezing level 1700 m.THURSDAY: Sunny, light southwest winds, alpine temperature 1 C, freezing level 2200 m.FRIDAY: A mix of sun and cloud, light southwest winds, alpine temperature 1 C, freezing level 2200 m.

Avalanche Summary

On Monday, loose wet avalanches were triggered naturally and by explosives. They were large (size 2 to 2.5) and on all aspects between 1700 m and 2100 m.

Snowpack Summary

An additional 15 to 25 cm of snow fell on Tuesday, for storm snow totals of 30 to 50 cm since Monday morning. The snow fell on a melt-freeze crust produced from rain and warm temperatures on Sunday. Numerous other melt-freeze crusts exist in the upper snowpack from rain, sun, and warming during the spring season. The snowpack below this is generally well-settled and strong.At lower elevations below treeline, a spring snowpack exists.

Problems

Loose Wet

Sunny skies and warming air temperatures will rapidly weaken the snow surface and increase the likelihood of triggering loose wet avalanches. Expect natural avalanches on steep slopes, particularly on south aspects under sunny skies.

Use caution above cliffs and terrain traps where small avalanches may have severe consequences.Avoid steep slopes when air temperatures are warm or solar radiation is strong.Use extra caution on slopes if the snow is moist or wet.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 2.5

Storm Slabs

Up to 50 cm of snow fell recently, which may not bond well to an underlying crust. Slabs may be more reactive adjacent to ridges in wind-loaded terrain. Watch your overhead exposure, as cornices could trigger slabs on slopes below.

Use extra caution around cornices: they are large, fragile, and can trigger slabs on slopes below.Observe for the bond of new snow with the old surface before committing into avalanche terrain.Be careful of wind-loaded pockets near ridges.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

1 - 2.5

Valid until: Apr 18th, 2018 2:00PM