Avalanche Forecast

Issued: Mar 5th, 2016 7:33AM

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

triley, Avalanche Canada

Cariboos.

Forecast new snow and wind will continue to develop storm slabs over surface hoar and crusts. Expect remote triggering and wide fracture propagations resulting in large avalanches. Conservative terrain selection is essential.

Summary

Confidence

Moderate - Intensity of incoming weather systems is uncertain on Sunday

Weather Forecast

Cloud developing Saturday evening, and then strong southerly winds with 5-10 cm of new snow overnight. The freezing level should dip down to 1000 metres overnight and then climb up to 1500 metres on Sunday. Another 5-10 cm of new snow during the day Sunday combined with strong southwest winds. Freezing levels dropping to valley bottoms by Monday morning. Mostly sunny on Monday with strong solar radiation and freezing levels around 1500 metres. Cloudy with light precipitation on Tuesday.

Avalanche Summary

Natural avalanches continued to release down 40-60 cm on Friday up to size 2.5. Reports from Thursday that several natural size 2.0 slab avalanches and one size 3.0 storm slab were suspected to have released on the late February surface hoar layer. There was also a report of a size 3.0 avalanche remotely triggered by a skier that was 20 metres away.

Snowpack Summary

New snow continues to develop the storm slab that is 40-60cm thick and bonding poorly to a crust on previously sun-exposed slopes and surface hoar (February 27th or late February) on shady and sheltered slopes. Thicker and touchier wind slabs are lurking throughout exposed terrain at and above treeline. A couple of sun crusts might exist in the upper 50-70cm on southerly aspects. The surface hoar and/or crust layer which was buried February 10 is now down around a metre and is still producing isolated hard sudden results in snowpack tests. Large cornices will be getting weak with warmer temperatures.

Problems

Storm Slabs

Forecast new snow and wind may continue to develop storm slabs at all elevations. Pockets of wind transported snow may release naturally or be easy to trigger.

Be cautious as you transition into wind affected terrain.>Minimize exposure during periods of heavy loading from new snow, wind.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely - Very Likely

Expected Size

1 - 4

Persistent Slabs

Buried surface hoar and/or a crust may be down 40-60 cm and easy to trigger with light additional loads or from travelling on adjacent terrain.

Be aware of the potential for large, deep avalanches due to the presence of buried surface hoar.>Choose well supported terrain without convexities.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely - Very Likely

Expected Size

2 - 5

Cornices

Cornices are large and fragile and may fall off with additional loading.

Cornices become weak with daytime heating. >Extra caution needed around cornices with current conditions.>

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

2 - 5

Valid until: Mar 6th, 2016 2:00PM