Avalanche Forecast

Issued: Mar 3rd, 2019 4:41PM

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

cgarritty, Avalanche Canada

Cariboos.

Avoiding wind-affected upper elevations is likely to lead you into sheltered areas where a tricky persistent weak layer may be well preserved. Keep your guard up at lower elevations by seeking out lower angle, lower consequence slopes.

Summary

Confidence

High -

Weather Forecast

Sunday night: Clear. Light east or northeast winds.Monday: Sunny. Light east or northeast winds. Alpine high temperatures around -11.Tuesday: Sunny with cloudy periods. Light east winds. Alpine high temperatures around -11.Wednesday: A mix of sun and cloud. Light to moderate southeast winds. Alpine high temperatures around -8.

Avalanche Summary

No new avalanches have been reported in the region over the past few days, but observations in neighbouring regions have shown regular, generally small (size 1) wind slabs reacting to skier traffic and ski cutting at higher elevations. Snowpack tests results highlighting ongoing weakness at our mid-January persistent weak layer as well as occasional persistent slab avalanches have been a regular feature of recent reports. A recent post from the VARDA team highlights ongoing concern for persistent slab problems in the Cariboos. See the link here.

Snowpack Summary

Weeks of mainly dry, windy, and cold weather have transformed the snowpack at upper elevations into a mix of wind-affected surfaces and wind slabs of varying ages on all aspects. These wind slabs have shown prolonged reactivity because of the faceted (weak, sugary snow) they overlie. In more sheltered areas at lower elevations, a weak layer buried in mid January can be found approximately 50-60 cm deep. This layer consists of surface hoar (weak, feathery crystals) and facets, and may be combined with a crust on south facing slopes. Avalanche activity on this layer has been on the decline, but snowpack test results continue to indicate this layer may still be possible to human trigger in specific locations. It has been most reactive in sheltered openings at lower elevations and especially below treeline.The lower snowpack is generally considered to be strong, except for shallow, rocky areas where cold temperatures continue to facet (weaken) the snowpack.

Problems

Wind Slabs

Recently formed wind slabs can be found on all aspects, but especially to the lee of recent northeast winds. These wind slabs have shown prolonged reactivity due to the weak, faceted snow they sit above.

Steep and rocky terrain are likely places to trigger buried wind slabs.Avoid wind loaded pockets, especially near ridge crests and roll-overs.Back off from slopes that sound hollow or drum-like.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Persistent Slabs

50-60 cm of snow sits above a persistent weak layer of surface hoar (weak, feathery crystals) that was buried in mid-January. This layer has evolved into a low likelihood, high consequence avalanche problem that is most prominent at lower elevations

Avoid low elevation cut-blocks where this layer is well preserved.Use conservative route selection, choose moderate angled terrain with low consequence.Avoid steep, open and/or sparsely treed slopes at and below treeline.

Aspects: All aspects.

Elevations: Treeline, Below Treeline.

Likelihood

Unlikely - Possible

Expected Size

1.5 - 2.5

Valid until: Mar 4th, 2019 2:00PM