Avalanche Forecast

Issued: Jan 19th, 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 and Wind Slabs.

conrad janzen, Parks Canada

Banff Yoho Kootenay.

Natural activity has tapered off, but human triggered avalanches in steep terrain are likely due to the basal weaknesses. This is not the time to venture into big terrain. CJ

Summary

Weather Forecast

Mainly sunny conditions with light west winds, no significant precipitation, and alpine temperatures between -3 and -10'C are forecast for the next few days.Â Freezing level near valley bottom on Monday, rising to 1800m on Tuesday and dropping to valley bottom again on Wednesday.

Snowpack Summary

Widespread wind slabs in lee and cross loaded features at tree line and above. Most windward features are scoured to ground from last weeks wind. Easy, sudden collapse compression test results in the basal depth hoar found at tree line on Hwy 93 N (E side of the highway). Some moist snow on steep solar aspects in the afternoon.

Avalanche Summary

Observed some small solar triggered moist sluffs to size 1, and and one notable size 3 on a S facing alpine feature near Mt. Hector which stepped down to the ground in the last 48hrs. Most natural activity has ceased. Evidence of the widespread cycle from the last week is sobering, with many features failing wall to wall on the basal weak layers.

Confidence

Problems

Deep Persistent Slabs

The frequency of full depth avalanches on the basal depth hoar/crust is slowing down, but any slope that has not avalanched should be treated with caution. It will be very high consequence if you trigger this layer.

Watch for whumpfing, hollow sounds, and shooting cracks.Be aware of the potential for full depth avalanches due to deeply buried weak layers.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

2 - 3

Wind Slabs

Wind slabs that have been triggered in the last couple days have provided enough weight to "step down" and trigger the basal weaknesses, resulting in larger than expected avalanches. Avoid steep lee loaded or cross loaded terrain.

Be cautious as you transition into wind affected terrain.Minimize overhead exposure; avalanches triggered by windloading may reach run out zones.

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 3

Valid until: Jan 20th, 2014 4:00PM