Avalanche Forecast

Issued: Nov 19th, 2017 8:08AM

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

Parks Canada ian gale, Parks Canada

Another stormy day today with heavy snowfall and wind loading.Expect natural avalanches today that could run to valley bottom.

Summary

Weather Forecast

Another stormy day! Today 20 cms are forecast, with 35km/hr winds from the Southwest.  Tonight we can expect another 10-15cm before a break between storms on Monday. Further out the current forecast shows another weather system Tuesday/Wednesday bringing precipitation and high freezing levels.

Snowpack Summary

We received another 14cm of snow in the last 24hrs, bringing the storm total to approx 80cm. The snow pack has almost doubled in the last week and a half! The Halloween crust is the layer we're watching and it's down approx 90cm.The Nov 9th is a hard to find & spotty surface hoar layer in the top 70cm.The snowpack remains shallow below 1700m

Avalanche Summary

Numerous avalanches to size 2 were observed in the highway corridor from very steep terrain on Mt MacDonald and Tupper in the last 48 hrs. There was also avalanche debris reported from steep north facing terrain in Cannaught creek drainage. This increase in avalanche activity can be attributed to recent snow loading and strong winds in the alpine.

Confidence

Intensity of incoming weather systems is uncertain

Problems

Storm Slabs

An icon showing Storm Slabs
Heavy snow loading and strong alpine winds have created a reactive storm slab in the alpine. The storm slab will be more reactive in unsupported terrain and ridgetop terrain features exposed to wind loading.
The new snow will require several days to settle and stabilize.Minimize overhead exposure during periods of heavy loading from new snow, wind.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 3

Persistent Slabs

An icon showing Persistent Slabs
The Halloween Crust layer is buried down approximately 90cms. With the recent loading from heavy snow and strong winds we could see this layer become reactive. If it does "wake up" the resulting avalanches would be large!
Minimize exposure during periods of heavy loading from new snow and wind.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

2 - 3

Valid until: Nov 20th, 2017 8:00AM