Avalanche Forecast

Issued: Apr 12th, 2019 4:00PM

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

tim haggarty, Parks Canada

Little Yoho.

Winds are expected to pick up to moderate overnight Friday and then to strong during the day Saturday. Recent snowfall has provided significant amounts for transport. Expect slab formation Saturday.

Summary

Weather Forecast

Following unsettled weather Friday, an organized low will cross the interior Saturday reaching the forecast region in the evening. Winds will increase to moderate west overnight Friday and again to strong west by mid-day Saturday. Freezing levels will again reach near 2000m Saturday with 5cm of snow expected above this.

Snowpack Summary

10 to 30cm has fallen since April 9 with light winds. Freezing levels reach roughly 2200m each day and modest solar inputs have created new crusts. Facets 50 to 70cm deep remain a concern on alpine North aspects. Shallow areas in the alpine are also of concern often displaying no consolidated mid-pack.

Avalanche Summary

A small skier triggered slab at the entrance of an alpine couloir today represents the recent snow starting to consolidate into a reactive slab near ridge crest.

Confidence

Problems

Wind Slabs

The first indications that recent snow has started to form a new slab are being reported. With winds expected to increase to moderate late Friday and then strong mid day Saturday, expect rapid development of new slabs.

If triggered the wind slabs may step down to deeper layers resulting in large avalanches.Minimize overhead exposure during periods of heavy loading from new snow, wind.

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Unlikely - Possible

Expected Size

1 - 1.5

Persistent Slabs

These slabs remain a concern on north aspects in the alpine where March winds built slabs over the facetted snow from February's cold snap. It is wise to check in on this layer now found 40- 70cm deep before venturing into committing terrain.

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

Aspects: North, North East, East.

Elevations: Alpine.

Likelihood

Unlikely - Possible

Expected Size

1 - 2

Valid until: Apr 13th, 2019 4:00PM