Avalanche Forecast

Issued: Mar 10th, 2018 4:22PM

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

mbender, Avalanche Canada

Kootenay Boundary.

Expect to see the first real warmup of the season with clear skies and rising freezing levels through the rest of the weekend into next week. Click this link to see our latest blog on the impact of warming.

Summary

Confidence

Moderate - Freezing levels are uncertain on Tuesday

Weather Forecast

SUNDAY: Mix of sun and cloud / Light south wind / Alpine temperature 1 / Freezing level 2000m MONDAY: Mix of sun and cloud / Light to moderate southwest wind / Alpine temperature 5 / Freezing level 2500m TUESDAY: Mix of sun and cloud / light south wind / Alpine temperature 7 / Freezing level 2700m

Avalanche Summary

On Friday reports indicate numerous size 2-2.5 natural and explosive controlled storm snow avalanches running on all aspects in the alpine and at tree line. There were also several skier triggered storm slab avalanche size 1.5-2 both Friday and Saturday on north aspects in the alpine and tree line. Expect to see a rise in solar triggered storm slab and loose wet avalanche activity in the coming days with clear skies and high freezing levels.

Snowpack Summary

Friday's 15-35cm of new snow has settled and been redistributed by predominantly west and southwest wind and sits on mostly unconsolidated snow from last week and on a sun crust on south-facing slopes.A mix of weak layers exist 50-100 cm below the surface, including small surface hoar on shady aspects and a crust on solar aspects. These layers have consistently been reactive in snowpack tests, suggesting they could potentially remain reactive to human triggers as well. Deeper weak layers that formed in January and December have gained strength and gone dormant at this time. They include several surface hoar and facet layers 1 to 2 m below the surface and a crust/ facet interface near the base of the snowpack.

Problems

Storm Slabs

Fresh storm and wind slabs have formed with with recent new snow combined with moderate southwesterly wind. With sun and warm temperatures in the forecast expect to see loose wet avalanches as well.

Extra caution needed around cornices with current conditions.Minimize exposure to steep, sun exposed slopes when the solar radiation is strong.Be careful with wind loaded pockets, especially near ridge crests and roll-overs.

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

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 2

Persistent Slabs

Weak layers exist 50-100 cm below the surface, including surface hoar on north-facing terrain and sun crusts on south-facing terrain. These layers may become reactive with the weight of new snow and warming.

Avoid convexities or areas with a thin or variable snowpack.Be cautious on convex rolls at and below treeline where buried surface hoar may be preserved.If triggered smaller avalanches may step down to deeper layers resulting in large avalanches.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

1.5 - 3

Valid until: Mar 11th, 2018 3:00PM