Avalanche Forecast

Issued: Jan 17th, 2015 8:01AM

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

Parks Canada andrew jones, Parks Canada

Newly formed wind slabs will be reactive today.

Summary

Weather Forecast

Strong SW winds are expected to continue today with trace amounts of precipitation.  A strong cold front associated with a deepening low pressure system will be moving into the area later tonight. Precipitation amounts are forecasted to be 5-10cm tonight and up to 20cm tomorrow. Avalanche hazard will increase with the new snow and sustained winds.

Snowpack Summary

20cm of new snow was exposed to strong overnight winds. In addition to a developing storm slab, expect a thicker wind slab on leeward micro features and N-NE aspects. The January 15 surface hoar layer down 15-25cm is widespread and sits on a crust on solar aspects. A cohesive slab sits on top of the Dec 17 surface hoar layer (down 70-120cm).

Avalanche Summary

Several large natural avalanches were observed yesterday during in paths facing the highway corridor. This avalanche cycle was a result of a developing storm slab in recent new snow.

Confidence

Problems

Wind Slabs

An icon showing Wind Slabs
New snow was exposed to strong overnight winds. In addition to a developing storm slab, expect a thicker wind slab on leeward micro features and N-NE aspects.  These newly formed slabs need time to bond to the old snow surface and will be reactive.
Stay off recent wind loaded areas until the slope has had a chance to stabilize.Pay attention to overhead hazards like cornices.

Aspects: North, North East, East.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 3

Persistent Slabs

An icon showing Persistent Slabs
The December 17th surface hoar layer is still a real concern. This layer is widespread at treeline and more spotty at alpine elevations. The surface hoar sits on a thick crust complex which provides a firm failure plane for avalanches.
Choose well supported terrain without convexities.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

2 - 3

Valid until: Jan 18th, 2015 8:00AM