Avalanche Forecast

Issued: Mar 4th, 2019 5:01PM

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.

cgarritty, Avalanche Canada

Cariboos.

Wind slabs and persistent slabs are becoming less likely to trigger, but conditions still demand assessment of suspect features in wind affected areas and in sheltered openings at lower elevations.

Summary

Confidence

Moderate -

Weather Forecast

Monday night: Clear. Light east winds.Tuesday: Sunny. Light east winds. Alpine high temperatures around -11.Wednesday: A mix of sun and cloud. Light to moderate southeast winds. Alpine high temperatures around -9.Thursday: Cloudy with scattered flurries bringing around 5 cm of new snow, continuing overnight. Light southwest winds. Alpine high temperatures around -10.

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 weakness at our mid-January persistent weak layer as well as occasional persistent slab avalanches have been a regular, but diminishing feature of recent reports. A recent post from the VARDA team highlights the importance of continued awareness of 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. Wind slabs have recently shown prolonged reactivity due to the weak, faceted snow they sit above.

Increase caution around wind loaded pockets near ridge crests and roll-overs.Steep and rocky terrain are likely places to trigger buried wind slabs.Minimize exposure to steep, sun exposed slopes when the solar radiation is strong.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 1.5

Persistent Slabs

50-60 cm of snow sits above a persistent weak layer of surface hoar buried in mid-January. This layer has evolved into a lower likelihood avalanche problem that still demands slope assessment and cautious group management at lower elevations.

Maintain diligent group management around open and/or sparsely treed slopes at treeline and below.Exercise increased caution around low elevation cut-blocks where this layer has been well preserved.

Aspects: All aspects.

Elevations: Treeline, Below Treeline.

Likelihood

Unlikely

Expected Size

1 - 2

Valid until: Mar 5th, 2019 2:00PM