Avalanche Forecast

Issued: Mar 9th, 2018 4:33PM

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

cgarritty, Avalanche Canada

Cariboos.

Winter is loosening its grip and a warming event is on its way. Surface instabilities should be the main concern on Saturday. Check out the Forecasters' Blog for more details: http://www.avalanche.ca/blogs/2018-03-09-first-big-warm-up

Summary

Confidence

Moderate - Timing or intensity of solar radiation is uncertain

Weather Forecast

Saturday: A mix of sun and cloud, becoming increasingly sunny. Light south winds, becoming strong in the alpine. Freezing level rising to 1500 metres with alpine temperatures around -3.Sunday: Mainly sunny. Light south winds. Freezing level rising to 1800 metres with alpine temperatures of -1.Monday: Sunny. Light southeast winds. Freezing level rising to 2100 metres with alpine temperatures around 0 to +1.

Avalanche Summary

Thursday's reports included one observation of an older size 2.5 natural wind slab release in the south of the region. This avalanche occurred on a 40 degree southwest slope in the alpine and had a depth of 60 cm.On Wednesday, a chunk of falling ice triggered a size 2.5 avalanche. On Tuesday, a few large cornice falls were reported, without releasing large avalanches on slopes below. A few loose wet solar-triggered avalanches were also observed.Avalanche activity is expected to increase as we move into a period of intense sun and prolonged warming. Predictable loose wet avalanches from steep, sunny terrain should be easy to manage. A trickier problem will gradually emerge as warmth penetrates into the snowpack to tickle deeper persistent weak layers that have lately been dormant in the Cariboos. The next few days will be a time to avoid exposure to large sunny features and keep well away from corniced slopes.

Snowpack Summary

Thursday's storm brought 20-30 cm of new snow by Friday morning. This new snow overlies well-settled storm snow from regular snowfalls over the past couple of weeks. Although several layers of sun crust can be found within this storm snow on solar aspects, recent snowpack tests have not been producing concerning results in the upper snowpack. 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 forecast 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. A weak layer of facets also lingers at the base of the snowpack.

Problems

Loose Wet

Sun on new snow is likely to lead to loose moist avalanches which could run surprisingly far. Large loose avalanches may also have potential to step down to deeply buried weak layers.

Choose regroup spots carefully, thinking about what is above you.Minimize exposure to steep, sun exposed slopes when the solar radiation is strong.Be cautious of sluffing in steep terrain, particularly where the debris flows into terrain traps.

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

Elevations: All elevations.

Likelihood

Likely - Very Likely

Expected Size

1 - 2

Storm Slabs

Our newly formed storm slabs may remain reactive to human triggering on Saturday. Solar aspects are especially concerning because of direct sunshine acting as a natural trigger and a higher likelihood for buried crust to act as a sliding layer.

Use extra caution on open slopes and convex rolls.Pay attention to cornices and give them a wide berth when travelling on or below ridges.If triggered, large storm slabs may step down to deeper layers and result in very large avalanches.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 2

Valid until: Mar 10th, 2018 2:00PM