Avalanche Forecast

Issued: Mar 21st, 2019 4:33PM

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

swerner, Avalanche Canada

Kootenay Boundary.

Natural avalanche activity is possible with the persistent warm temperatures. Cornices are soft and weak. Avoid travel under, on or anywhere near cornices.

Summary

Confidence

Moderate -

Weather Forecast

The weather pattern begins to change Friday with increased cloud cover and falling freezing levels overnight. FRIDAY: Mix of sun and cloud. Freezing levels 3000 m with an alpine high of + 6 degrees. Ridgetop winds light from West.SATURDAY: Cloudy with light rain at lower elevations and light snow in the alpine. Freezing levels falling to 1700 m and alpine temperatures near -1. Ridgetop winds light from the southwest. SUNDAY: Cloudy with light rain at lower elevations and 5-10 cm of snow in the alpine. Freezing levels 1700 m and alpine temperatures near -1. Ridgetop winds light from the southwest.

Avalanche Summary

On Wednesday, natural loose wet avalanches continue on solar aspects up to size 2.5 through the region.Natural avalanche activity will likely taper off on the weekend when temperatures and freezing levels start to drop to seasonal norms.

Snowpack Summary

Currently, solar aspects are showing signs of melt by day and a freeze by night. Only the upper 10-20 cm is re-freezing into a solid crust which breaks down by noon. Most solar slopes at lower elevations are becoming isothermal. You can still find dry, wintery snow on North facing slopes in the alpine and variable wind effect remains. The bigger questions are deeper in the snowpack. Two crusts exist in the upper snowpack and the bond of the overlying snow is most concerning. The first crust is down 20 to 30 cm and loose wet avalanches have slid on this interface. The deeper one down 60-95 cm has also produced easy shears in test profiles and is potentially just waiting for enough heat to penetrate, creating a cohesive slab that may avalanche, if it does?

Problems

Loose Wet

Loose wet activity is expected to continue on most aspects and elevations. Cornices are softening up and becoming weak. You don't want to be under or near one of these looming monsters when they fail.

Avoid slopes when the solar radiation is strong, especially if they have large cornices overhead.Avoid exposure to terrain traps where the consequences of a small avalanche could be serious.

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

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 2

Persistent Slabs

Warm temperatures are penetrating deeper into the snowpack and a cohesive slab now sits above a series of weak layers.

The likelihood of deep persistent slab avalanches will increase with each day of warm weather.Smaller loose wet avalanches may step down to weaker layers initiating large avalanches.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

1.5 - 3

Valid until: Mar 22nd, 2019 2:00PM