Avalanche Forecast

Issued: Mar 15th, 2017 4:43PM

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

Avalanche Canada rbuhler, Avalanche Canada

The new snow and strong wind is expected to form new wind slabs that will bury the rain crust. If more than around 30 cm of snow accumulates in your riding area, a more widespread storm slab problem may develop and local hazard could be High.

Summary

Confidence

Low - Due to the number of field observations

Weather Forecast

Light to moderate snowfall is expected Wednesday overnight and for most of the day on Thursday. 10-15 cm is expected overnight with another 15-20 cm during the day. Freezing levels are expected to be around 600 m early Thursday morning and reach around 1000 m in the afternoon. Alpine wind is forecast to be moderate to strong from the southwest for most of the day. Snowfall is forecast to continue Thursday overnight and during the day on Friday with the current forecast for another 15-30 cm. Freezing levels are forecast to remain below 1200 m during this period and alpine wind should remain moderate to strong from the south and southwest. The last significant storm pulse is currently forecast for Saturday with 20-30 mm currently forecast during the day and freezing levels reaching around 1500 m.

Avalanche Summary

No new avalanches have been reported recently but observations have been very limited during the warm storm. On Thursday, the new snow will bury the widespread surface crust and is expected to form new wind slabs in exposed terrain. At lower elevations, rain may result in wet sluffing from steep terrain features.

Snowpack Summary

Heavy rain has saturated the upper snowpack well into the alpine. As temperatures drop, a widespread crust layer is expected to form.  New snow on Thursday will bury this crust and strong alpine wind is expected to form wind slabs.The late February weak layer is now down 1.5 m or more in the snowpack and is now expected to have become unreactive. This layer is composed of a sun crust on southerly aspects and surface hoar on shaded aspects. The snowpack is generally well settled and strong below this layer.

Problems

Wind Slabs

An icon showing Wind Slabs
The new snow with strong alpine wind is expected to form new wind slabs on Thursday. These slabs will sit over a crust in many areas and are expected to be touchy. Cornices are also reported to be large and may still be weak.
Give cornices a wide berth when travelling on or below ridges.Avoid freshly wind loaded features.Be alert to conditions that change with elevation.

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

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 2

Loose Wet

An icon showing Loose Wet
At lower elevations, sustained rainfall may destabilize the snowpack and sluffing is possible on steep slopes.
Be cautious of sluffing in steep terrain.Use extra caution on steep slopes if the snow is wet.

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Mar 16th, 2017 2:00PM

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