Avalanche Forecast

Issued: Feb 19th, 2017 3:45PM

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

mgrist, Avalanche Canada

Cariboos.

The best riding right now is probably on high north aspects, which is also where the hazard is the highest. Don't let your guard down when searching for fresh powder.

Summary

Confidence

Moderate - Due to the number of field observations

Weather Forecast

We're into a fairly stable weather pattern: seasonal temperatures and isolated flurries.MONDAY: Cloudy with light flurries, local accumulations 5-10cm, light to moderate southwesterly winds and freezing levels around 1300 m.TUESDAY: A mix of sun and cloud with light snow flurries starting in the evening (5-10cm), light winds and freezing levels around 700 m.WEDNESDAY: Cloudy with light flurries, light southerly winds and freezing levels around 400 m.

Avalanche Summary

We had reports of a machine-triggered wind slab avalanche (Size 2) on a steep northeast aspect at 2100m on Saturday. Touchy new wind slabs are likely sensitive to light triggers and have the potential to step down and trigger persistent slab avalanches.

Snowpack Summary

We've had little change over the weekend with only about 3-5cm new snow. Expect to find 10-25 cm of more recent snow blown into deep wind slabs at higher elevations, and moist snow or breakable crust below 1500m. Settling snow (40-60cm) from last week is still bonding poorly to the previous snow surface from early February, which is now down 50-80 cm and includes a sun crust on steep sun-exposed slopes, faceted snow, as well as surface hoar on sheltered open slopes. The persistent weakness buried mid-January is now down around 80-100 cm and the surface hoar/facet weakness buried mid-December is down 100-150 cm. These deep persistent weaknesses still have the potential to wake up and become reactive with human triggers.

Problems

Wind Slabs

Touchy wind slabs are likely lurking below ridge crests and behind terrain features at higher elevations.

If triggered the wind slabs may step down to deeper layers resulting in large avalanches.Use ridges or ribs to avoid pockets of wind loaded snow.Avoid recently wind loaded features.

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Persistent Slabs

A persistent weakness down 40-70 cm remains remains sensitive to light triggers in isolated areas. Smaller avalanches have the potential to step down to this and deeper persistent weakness resulting very large avalanches.

Use conservative route selection, choose moderate angled and supported terrain with low consequence.Whumpfing, shooting cracks and recent avalanches are all strong indicators of unstable snowpack.Be aware of the potential for large, deep avalanches due to the presence of buried weak layers.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

2 - 4

Valid until: Feb 20th, 2017 2:00PM