Avalanche Forecast

Issued: Mar 11th, 2018 5:07PM

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

mgrist, Avalanche Canada

Cariboos.

Avalanche danger will increase in the afternoon with strong solar input and warming temperatures. Concern for persistent slab problems is on the rise.See the Forecaster's Blog for more: http://www.avalanche.ca/blogs/2018-03-09-first-big-warm-up

Summary

Confidence

Moderate - Due to the number of field observations

Weather Forecast

Sunny and warm until our next weather system arrives late Wednesday. MONDAY: Sunny. Light southeast winds. Freezing level rising to 2500 metres with alpine high temperatures around 0 to +1.TUESDAY: Mainly sunny. Light southeast winds, increasing over the day. Freezing level to 2500 metres with alpine high temperatures of +2.WEDNESDAY: Cloudy with isolated flurries in the afternoon. Light south winds. Freezing level near 2000 metres with alpine high temperatures of +1.

Avalanche Summary

Reports from Saturday included wet loose avalanches to size 1.5. These occurred in steeper terrain on sunny aspects. On Friday, numerous recent wind slab releases were also observed to have run naturally up to size 2.5 on steeper north aspects.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.Avalanche activity is expected to increase as we move into a period of intense sun and prolonged warming. Predictable wet loose 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 been dormant for awhile now 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 older 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.

Problems

Loose Wet

Sun on new snow is likely to lead to loose wet 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

Expected Size

1 - 1.5

Wind Slabs

Wind slabs formed on all aspects during the recent storm and they may remain reactive on Monday. Extra caution is needed on solar aspects where sunshine could act as a natural trigger with a buried sun crust as a sliding layer.

Pay attention to cornices and give them a wide berth when travelling on or below ridges.If triggered, large wind slabs may step down to deeper layers and result in very large avalanches.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2.5

Valid until: Mar 12th, 2018 2:00PM