Avalanche Forecast

Issued: Jan 3rd, 2014 4:00PM

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

Stephen Holeczi, Parks Canada

Banff Yoho Kootenay.

Watch locally for N/NW winds in the next 24 hours. It wont take much to cause the hazard to go to High at upper elevations. We still have an overall weak snowpack, and have low confidence in bigger terrain. Ski quality is good in sheltered areas.SH

Summary

Weather Forecast

A N/NW flow with light - mod. winds will dominate for the next few days, with temperatures cooling to -15C Friday night. Expect a clearing trend with a trace of snow Friday night and none expected for the weekend

Snowpack Summary

20-30cm fell(tapering off to the W) in the last 24 hours, with little wind effect overall. 100cm at treeline on average. This new snow overlies previous wind slabs which sit over the basal depth hoar/ crust. Mod compression results found today at treeline on Hwy 93.N, collapsing in the depth hoar. More supportive midpack W of the divide.

Avalanche Summary

Numerous avalanches to sz. 2.5 stepping to ground were observed in the alpine today on numerous aspects, but a widespread avalanche cycle did not occur (probably due to lack of wind). A size 2 poured over Pilsner Pillar on Mt. Dennis and left of Silk Tassel on Mt. Field. We have been seeing isolated slides like this every day for over a week.

Confidence

Due to the number of field observations on Friday

Problems

Deep Persistent Slabs

This is the main layer of concern. Full depth avalanches on the basal depth hoar and crust have been occurring every day in the last week. The new snow has added stress to this layer, and will be easiest to trigger this layer in thin snowpack areas.

Be aware of thin areas that may propogate to deeper instabilites.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

2 - 3

Wind Slabs

Watch for areas of wind loading or open areas with wind effect. If a wind slab is triggered it may step down to the weak basal layers. The new snow will be hiding these wind slabs in many areas.

Be careful with wind loaded pockets while approaching and climbing ice routes.Avoid freshly wind loaded features.

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

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

2 - 3

Loose Dry

The 20-30 cm of new snow can be expected to slough with any wind that occurs over the next 24 hours. Ice climbers should especially watch for sloughing in steep gully features and terrain traps.

Be cautious of sluffing in steep terrain.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 2

Valid until: Jan 4th, 2014 4:00PM