Avalanche Forecast

Issued: Dec 25th, 2017 3:59PM

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

jmcbride, Avalanche Canada

South Coast Inland.

The southern part of the region continues to be the driver for elevated hazard levels. Although wind slabs remain a concern in northern areas.Ho, ho, hopefully the whole region will see some appreciable snowfall later in the week!

Summary

Confidence

Moderate - Forecast snowfall amounts are uncertain on Thursday

Weather Forecast

TUESDAY: Mix of sun and cloud. Ridge wind light from the west. Temperature -12. Freezing level surface.WEDNESDAY: Mostly cloudy, flurries. Accumulation trace. Ridge wind moderate from the southwest. Temperature -10. Freezing level surface.THURSDAY: Snow. Accumulation 5 - 15 cm. Ridge wind moderate to strong from the southwest. Temperature -5. Freezing level 400 m.

Avalanche Summary

There have been no new reports of avalanches since last week when southern areas saw numerous loose dry to Size 1.5, as well as slab and glide avalanches to Size 2 on steep, leeward terrain and smooth rock slabs, while the northern part of the region reported wind slab activity up to size 2 on north and west aspects in the alpine.

Snowpack Summary

The recent storm snow has been redistributed by moderate to strong northerly winds in the alpine and exposed treeline areas, creating both hard and soft wind slabs in lee areas and scouring windward areas. Soft unconsolidated snow can still be found in sheltered areas at treeline and below.The southern part of the region has seen impressive storm snow totals (90-150cm) in the past seven days, compared to northern areas of the region, which received 25-35cm. This new snow sits on crusts of variable thickness that formed on almost all aspects in mid-December (December 15th layer). On steep southerly aspects this crust is supportive, whereas on northerly aspects it is quite thin and variable. Beneath the December 15th layer the snowpack is well settled. The late November rain crust is now buried 50-80 cm in the northern part of the region and well over 1 m in the south. Great conditions reports from the north of the region are posted on the Mountain Information Network (MIN) here, as well as from the southern part of the region, here, and here.

Problems

Wind Slabs

Variable winds have created wind slabs on most aspects in the alpine and exposed treeline areas. These slabs overlie the December 15th crust and may still be reactive to light loads such as a skier or rider.

Be cautious as you transition into wind affected terrain.Watch for stiff or hollow feeling snow, whumpfing, or shooting cracks.Be careful with wind loaded pockets, especially near ridge crests and roll-overs.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Loose Dry

It may be possible to trigger a storm snow release on steep or convex terrain in areas sheltered from the wind, particulary in the southern part of the region where 80-100 cm of new snow fell last week.

Be cautious of sluffing in steep terrain.Use caution above cliffs and terrain traps where small avalanches may have severe consequences.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Unlikely

Expected Size

1 - 2

Valid until: Dec 26th, 2017 2:00PM