Avalanche Forecast

Issued: Mar 6th, 2018 3:52PM

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

pgoddard, Avalanche Canada

Cariboos.

Avalanche danger will spike higher than forecast on slopes that are being cooked by the sun.

Summary

Confidence

Moderate - Due to the number of field observations

Weather Forecast

WEDNESDAY: Mix of sun and cloud with flurries. Treeline temperature near -10. Light south-westerly winds.THURSDAY: Mix of sun and cloud with flurries. A few cm snow overnight. Treeline temperature near -8. Light south-westerly winds.FRIDAY: Mix of sun and cloud with flurries. Treeline temperature near -5. Light westerly winds.

Avalanche Summary

No avalanches have been reported since Sunday, when several cornice falls were reported. Late last week, a very large deep persistent slab released naturally in the west of the region.

Snowpack Summary

Recent storm snow continues to settle and dry out. Variable recent winds have left behind wind slabs on many slopes at treeline and above. These are expected to heal within a day or two. Direct sun is likely to weaken surface snow layers and give cornices a bit of an extra nudge too.Persistent weak layers from early January and mid-December are still being reported by local operators. They are generally considered dormant, but could wake up with significant warming, a surface avalanche stepping down, a cornice fall, or a human trigger in a shallow or variable-depth snowpack area. These layers consist of sun crust, surface hoar and/or facets. They seem to be most concerning where they are associated with a sun crust on solar aspects. Facets linger at the base of the snowpack.

Problems

Wind Slabs

Recent variable winds have left behind slabs in the lee of ridges and ribs. Cornices are fragile and may fall with solar warming.

Give cornices a wide berth when travelling on or below ridges.Travel on ridgetops to avoid wind slabs on slopes below.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Persistent Slabs

Persistent slabs are most likely to be triggered by a large load like a cornice fall; or by a person in a thin or variable-depth snowpack area.

Avoid steep convexities or areas with a thin or variable snowpack.Cornices become weak with daytime heating and could trigger a persistent slab on the slope below.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Unlikely - Possible

Expected Size

2 - 3

Valid until: Mar 7th, 2018 2:00PM