Avalanche Forecast

Issued: Mar 24th, 2019 5:04PM

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

ghelgeson, Avalanche Canada

Kootenay Boundary.

Although temperatures have cooled slightly, human triggered loose wet avalanches remain a concern on Monday, especially at mid & lower elevations where the snowpack remains weak, warm and mushy.

Summary

Confidence

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

Weather Forecast

We're moving into a weather pattern more in keeping with seasonal norms. Monday night's storm should offer a nice refresh at upper elevations and temperatures should remain cool(ish), at least through Wednesday morning.SUNDAY NIGHT: Light south/southeast wind, freezing level lowering to around 1500 m, trace to 5 cm of snow possible.MONDAY: Overcast clearing to scattered cloud cover throughout the day day, light southwest wind, freezing level topping out around 2000 m, no significant precipitation expected during the day.MONDAY NIGHT: Freezing level lowering to about 1500 m with 2 to 8 mm of precipitation expected. This will likely start as rain at lower/mid elevations and should produce a trace to 10 cm of snow at upper elevations. TUESDAY: Broken cloud cover, moderate to strong southwest wind, freezing level holding around 1500 m, 3 to 10 cm of snow possible.WEDNESDAY: Clear skies with cloud cover increasing throughout the day, light northeast wind, freezing level rising to about 1900 m, no significant precipitation expected.

Avalanche Summary

No new avalanche activity to report from Saturday. On Friday natural loose wet activity to size 2 was reported throughout the region.

Snowpack Summary

The current snow surface is quite variable. On higher north aspects above 2000 m you may find some dry, faceted snow. Some of this has been redistributed by southwesterly and northerly winds which may have formed isolated old wind slabs. We're looking at a good overnight refreeze on Sunday night, so most surfaces should have a supportive surface crust Monday morning. The two crusts in the upper snowpack are our biggest concern. The first crust is down 20 to 30 cm and loose wet avalanches have recently slid on this interface. The deeper one down 60 to 95 cm has produced easy shears in test profiles. Avalanches on this interface are unlikely, but possible. The snowpack at mid and upper elevations is expected to continue to gain strength as we enter a period of consecutive nights with below freezing temperatures.

Problems

Loose Wet

After a week of warmth we're entering a cooler period which should curtail natural avalanche activity. It may be possible to trigger slow moving yet powerful loose avalanches at mid and lower elevations where snow remains wet, weak, warm and mushy.

Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet.Avoid exposure to terrain traps where the consequences of a small avalanche could be serious.Cornices become weak with daytime heating, travel early on exposed slopes.

Aspects: All aspects.

Elevations: Treeline, Below Treeline.

Likelihood

Possible

Expected Size

1 - 1.5

Persistent Slabs

We're uncertain about how the upper 20 to 30 cm is bonding to a layer of weak faceted snow. This layer is likely most problematic on northerly aspects above 2000 m, where it may be associated with hard, wind-affected snow.

Avalanche hazard may have improved, but be mindful that buried instabilities are still present.When a thick, melt-freeze surface crust is present, avalanche activity is unlikely.

Aspects: North, North East, North West.

Elevations: Alpine.

Likelihood

Unlikely - Possible

Expected Size

1.5 - 2.5

Valid until: Mar 25th, 2019 2:00PM