Avalanche Forecast

Issued: Mar 8th, 2019 4:02PM

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

mconlan, Avalanche Canada

Kootenay Boundary.

Variable snowfall amounts accumulated across the region. The snow may be reactive on Saturday, either as soft slabs or loose snow. The persistent slab problem still exists and is best controlled by diligent group management.

Summary

Confidence

Moderate - Forecast snowfall amounts are uncertain

Weather Forecast

FRIDAY NIGHT: Cloudy with isolated snowfall, accumulation 1 to 3 cm and locally higher amounts possible, light variable wind, alpine temperature -11 C.SATURDAY: Cloudy with isolated snowfall, trace accumulation, light variable wind, alpine temperature -10 C.SUNDAY: Clear skies, light northwest wind, alpine temperature -9 C, freezing level 1300 m.MONDAY: Clear skies with afternoon clouds, light to moderate southwest wind, alpine temperature -7 C, freezing level 1400 m.

Avalanche Summary

Numerous small (size 1) loose dry avalanches were observed in treeline and alpine terrain on Thursday, being triggered naturally and by skiers.

Snowpack Summary

Around 15 to 25 cm of recent snow overlies wind-affected snow in exposed terrain, soft and faceted snow in sheltered areas, and a melt-freeze crust on southerly aspects.Two layers of weak and feathery surface hoar crystals are buried in the snowpack between 40 and 80 cm deep, which were buried mid-February and early-February. The layers may be associated with a melt-freeze crust on southerly aspects. These layers remain reactive in snowpack tests and have produced sporadic avalanches in the region over the past week.

Problems

Storm Slabs

The recent snow may remain loose in certain areas but may transition into a slab as settlement continues. The snow may be most reactive in steep terrain, which is also where the consequence may be the highest.

Use caution in freshly wind-loaded features, especially near ridge crests and in steep terrain.Assess the bonding of the new snow with underlying layers as you travel.Watch for signs of slab formation throughout the day.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Persistent Slabs

Two layers of weak surface hoar and/or a crust are buried 40 to 80 cm. Recent activity has been between 1700 m and 2200 m and on southwest to southeast aspects. The problem is best controlled with appropriate group management.

Apply caution around sheltered and open areas at treeline and below. Space out to limit exposure.Choose moderate-angled terrain with low consequence, avoiding terrain traps.

Aspects: All aspects.

Elevations: Treeline, Below Treeline.

Likelihood

Unlikely - Possible

Expected Size

1 - 2

Valid until: Mar 9th, 2019 2:00PM