Avalanche Forecast

Issued: Mar 17th, 2017 4:00PM

The alpine rating is high, the treeline rating is high, and the below treeline rating is high. Known problems include Persistent Slabs, Wind Slabs and Loose Wet.

stephen holeczi, Avalanche Canada

Little Yoho.

Another storm on the way will keep the danger ratings elevated through the weekend. Avoid avalanche terrain.

Summary

Weather Forecast

Another pulse of snow coming through Saturday although forecast amounts have shrunk somewhat. Expect 20 to 30cm with moderate to strong alpine winds and freezing levels to 2000m. This means rain will fall at lower elevations. On Sunday precipitation will taper off with moderate alpine winds and temperatures will drop off to -15 to 18C.

Snowpack Summary

30-60cm of recent snow and wind have continued to build significant load over midpack facets. The mix of previous rain, warm temperatures, and this new snow is overloading buried storm and windslabs, as well as the deeper facet layers which have woken up. Cooling Friday slowed the natural cycle, but only just.

Avalanche Summary

Many avalanches up to size 4 in the past 3 days on all aspects and elevations, in many cases reaching historical maximums . Avalanche control on Hwy. 93 South produced results to size 3.5 showing it is still extremely sensitive.

Confidence

Problems

Persistent Slabs

Several buried weak layers in the middle of the snowpack have become reactive again this week and should remain that way through this weekend. Once triggered, these will be very large in magnitude.

Dig down to find and test weak layers before committing to a line.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Very Likely

Expected Size

3 - 4

Wind Slabs

Wind slabs up to 1 meter deep exist at higher elevations, and in specific wind effected areas near treeline. Expect these to continue growing with additional inputs.

Use caution in lee areas. Recent wind loading have created wind slabs.

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

Elevations: Alpine, Treeline.

Likelihood

Very Likely

Expected Size

2 - 3

Loose Wet

With rain possible to 2000m on Saturday, loose wet avalanches can't be counted out. Gully terrain and steep cliffs will be likely areas. Climbers take note.

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Likely

Expected Size

1 - 2

Valid until: Mar 18th, 2017 4:00PM