Avalanche Forecast

Issued: Jan 31st, 2019 5:26PM

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

jsmith, Avalanche Canada

Kootenay Boundary.

Fresh storm slabs will form on a variety of surfaces and be primed for human triggers. Start in simple terrain without consequence to assess the bond of the new snow and avoid large avalanche paths.

Summary

Confidence

Moderate - Timing, track, or intensity of incoming weather system is uncertain

Weather Forecast

THURSDAY NIGHT: Cloudy with flurries; 1-3 cm. / Light, southwesterly winds / Low -3/ Freezing level below valley bottom.FRIDAY: Snow, 15-25 cm. / Moderate, southwesterly winds / High -2 C / Freezing level valley bottom. SATURDAY: Cloudy with sunny periods / Light, southerly winds / High -2 C / below valley bottom.SUNDAY: Cloudy with flurries; 3-5 cm. / Light, northwesterly winds / High-5 C / Freezing level below valley bottom.

Avalanche Summary

No avalanches were reported in the region on Wednesday. However, fresh storm slabs reactive to human triggers will form on Friday.

Snowpack Summary

There is currently a wide variety of snow surfaces. Sun crusts on south aspects to mountaintops, some of which have small surface hoar(weak, feathery crystals) growing on top, which is a particularly nasty combination. Most exposed alpine areas have been heavily wind effected. 5-10 mm surface hoar has been widespread in areas that are protected from sun and wind.Around 20 to 40 cm down, expect to find a crust on south aspects and feathery surface hoar crystals in sheltered and shaded areas. The surface hoar is currently the primary layer of concern and may be most reactive at treeline elevations on shady aspects. However, no recent avalanches have been reported on this layer.The remainder of the snowpack is generally well-settled and strong in most locations.

Problems

Storm Slabs

Fresh storm slabs will form on a variety of surfaces and will be primed for human triggers.

Watch for whumpfing, hollow sounds, shooting cracks or recent avalanches.Stay alert to changing conditions with elevation.Use small slopes without consequence to test the bond of the new snow.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 2

Persistent Slabs

40-60 cm of snow sits above crusts and a weak layer of surface hoar. The surface hoar is likely most pronounced in shaded and sheltered areas at treeline.

Smaller storm slab avalanches in motion could 'step-down' and trigger this layer.Avoid large slopes that would have big consequence if this deeper layer was triggered.

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

Elevations: Treeline, Below Treeline.

Likelihood

Unlikely - Possible

Expected Size

1 - 2

Valid until: Feb 1st, 2019 2:00PM