Avalanche Forecast

Issued: Feb 4th, 2017 4:00PM

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

stephen holeczi, Parks Canada

Banff Yoho Kootenay.

Current forecasts predict 20-25cm over the next 48 hours at treeline and above. If this holds true ski quality will improve, but sensitivity to triggering will increase. We have low confidence in the overall weak snowpack. SH

Summary

Weather Forecast

Mainly light East winds with gusts into the moderate range for Sunday. Current forecasts are showing 6-8cm Saturday night, 6-8cm Sunday, and 7-9 cm Monday. There is still quite a bit of uncertainty around snow amounts for this time period. Alpine highs will be in the -15C range for Sunday, and into the -20's for Monday.

Snowpack Summary

5 - 15cm in the last 24 hours. This sits on harder wind pressed surfaces from previous strong W/SW winds at treeline and above. Surface hoar may be found buried in sheltered locations. Generally the midpack is weak at TL and above, and the entire snowpack is weak BTL. Near the divide, deeper snow-packs are a bit stronger and more supportive.

Avalanche Summary

No new avalanches were seen or observed in the last 48 hours.

Confidence

Forecast snowfall amounts are uncertain on Sunday

Problems

Deep Persistent Slabs

The snowpack is weak. Slopes where a slab sits over the deeper weak layers should be treated as suspect. Increasing load and further slab development will make these slabs more sensitive Sunday and Monday.

Use conservative route selection, choose moderate angled and supported terrain with low consequence.Be aware of thin areas that may propogate to deeper instabilites.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

2 - 3

Storm Slabs

Small in size currently, watch locally for their formation and the bed surface they are lying on. There are wind layers, facets, surface hoar and sun crust depending on location. If there is increased E wind, watch for reverse loading.

Keep an eye out for reverse loading created by an upslope storm.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Valid until: Feb 5th, 2017 4:00PM