Avalanche Forecast

Issued: Dec 26th, 2014 8:02AM

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

Parks Canada ali haeri, Parks Canada

http://www.pc.gc.ca/apps/links/goto_e.asp?destination=http://www.facebook.com/ParksMountainSafetyNice weather weather is on the way but the instabilities we have within our snowpack are not likely to heal anytime soon. Cautious backcountry travel and wise decision making will be needed.

Summary

Weather Forecast

A high pressure ridge is slowly building over the Interior with a more northerly flow. Forecast is for overall clearing with a weak disturbance passing over the Province tonight into tomorrow morning. Light snow, ~5mm and light to moderate westerly winds tonight. Clearing by Sunday, cold temperatures and dry conditions will prevail for the week.

Snowpack Summary

Up to 15cm overnight on top of the 50-70cm deep storm slab sits on a well preserved and widespread Dec 17th surface hoar layer (10-20mm). The surface hoar sits on top of a rain crust up to 2100m, and on well settled snow above 2100m. The Dec 9th surface hoar layer is down 80cm in the area. The Nov 9th crust is 30cm up from the ground.

Avalanche Summary

Yesterday1 natural avalanche size 2.5 east of the Rogers Pass summit north aspect from one of the gullies off of Mt Macdonald. Artillery control from two days ago produced numerous avalanches up to size 3.5 showing wide propagation within the highway corridor. Some stepping down to deeper layers.

Confidence

Due to the number of field observations

Problems

Storm Slabs

An icon showing Storm Slabs
A widespread touchy surface hoar layer down 50 to 70cm is likely to be triggered anywhere it has not yet failed. As the slab overtop stiffens it becomes less likely to trigger but  propagation and consequences will increase. click photo
Avoid paths that have not avalanched recently.Whumpfing, shooting cracks and recent avalanches are all strong inicators of unstable snowpack.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

2 - 3

Deep Persistent Slabs

An icon showing Deep Persistent Slabs
Storm slab avalanches may step down to deeper layers, including the the Nov 9 layer at the bottom of the snowpack. The resulting avalanche would be very large.
Avoid shallow snowpack areas where triggering is more likely.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely

Expected Size

3 - 4

Valid until: Dec 27th, 2014 8:00AM