Avalanche Forecast

Issued: Feb 16th, 2020 5:00PM

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

Avalanche Canada shorton, Avalanche Canada

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As the weather improves the next few days keep in mind there has been a lot of recent snow and triggering large avalanches remains a concern.

Summary

Confidence

Moderate - A small change in the upper snowpack could dramatically change avalanche conditions.

Weather Forecast

SUNDAY NIGHT: Light flurries with up to 5 cm of new snow, moderate northwest wind, alpine temperatures drop to -10 C.

MONDAY: Mix of sun and cloud with some isolated flurries, moderate northwest wind, alpine high temperatures around -7 C.

TUESDAY: Sunny with a few clouds, light northwest wind, alpine high temperatures around -7 C.

WEDNESDAY: Sunny, moderate south wind, alpine high temperatures around -5 C.

Avalanche Summary

Steady snowfall and wind over the past week has resulted in storm slab and wind slab avalanches. On Friday, a natural cycle of size 1-2 avalanches occurred, primarily in wind affected terrain. Several small (size 1) human triggered slabs were also reported on Friday, and one large (size 2.5) wind slab was triggered by a skier on a northeast aspect at 2000 m. This MIN report shows an example of a recent snowmobile triggered wind slab from the neighbouring Clemina area. Reports of whumpfing at Sugarbowl on Saturday suggest recent snow could be settling into a reactive storm slab in sheltered terrain as well.

Snowpack Summary

A stormy week has delivered up to 100 cm of new snow to the Cariboos. The deepest reported amounts are along the Robson Valley and around Blue River, while most parts of the region received at least 40 cm. Up to now it has primarily been a problem on wind-loaded slopes, but as this snow settles into a slab it could become reactive on sheltered slopes too. In some areas this new snow may sit above small surface hoar (in open terrain at treeline), sun crusts (in open south-facing terrain), or a thick rain crust (below 1700 m). Overall there is some uncertainty about where and when recent storm snow may develop into reactive slabs.

The mid and lower snowpack are generally well settled and strong as two deeper layers have trended towards being unreactive under the current conditions, including; 1) an aging surface hoar layer from late December over 100 cm below the surface on treeline slopes in southern parts of the region, and 2) a facet/crust layer from November found near the ground in shallower snowpack areas.

Terrain and Travel

  • Start on smaller terrain features and gather information before committing to bigger terrain.
  • Avoid freshly wind loaded features, especially near ridge crests, roll-overs and in steep terrain.
  • Use caution when approaching steep and rocky terrian.
  • Minimize exposure to sun-exposed slopes when the solar radiation is strong.

Problems

Storm Slabs

An icon showing Storm Slabs

40-100 cm of recent snow could form large storm slabs. This snow has been reactive in steep wind affected terrain and is potentially settling into storm slabs in sheltered terrain as well.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

1 - 2.5

Valid until: Feb 17th, 2020 5:00PM

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