Avalanche Forecast

Issued: Mar 22nd, 2014 8:08AM

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

ali haeri, Parks Canada

Glacier.

Solar activity is not expected to be a factor today however that may change. A short burst of sun goes a long way into the snowpack. It will affect the weak layers and increase the overhead cornice hazard.

Summary

Weather Forecast

Weak low will approach the interior today. Increasing cloudiness and light snow is forecast with light south west winds into tomorrow morning. Ridge then rebuilds on sunday keeping conditions mostly clear and dry.

Snowpack Summary

The upper snowpack is 70cm of settling snow. The Mar 13 (down ~50-70cm) and the Mar 2 (down ~1m) crust/surface hoar layers are reactive in snowpack tests where they exist. The Feb 10-Jan22 layers are down 1.5-2m and continue to show the potential for big avalanches.

Avalanche Summary

Size 3.0 natural slab avalanche, cornice trigger, in Grizzly Bowl yesterday, east aspect, 2500m. A skier accidental from Bruins Ridge, down 20cm, 20-30m wide, east aspect. Skiers reported hearing many whoomphs on the rolling terrain to Little Sifton. 4 natural avalanches were observed in the highway corridor from size 2.0 to 2.5 yesterday morning.

Confidence

Intensity of incoming weather systems is uncertain on Sunday

Problems

Storm Slabs

Trickling snow over the last 4 days amounted to 60cm at tree line. Instabilities in the upper snowpack from the recent snow load may exist particularly in exposed areas that saw some wind.

Be cautious as you transition into wind affected terrain.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Persistent Slabs

Reports of whoomphing and natural activity observed on this layer yesterday indicate it's volatility. This layer is deep enough to cause a large avalanche and shallow enough to be human triggered, a dangerous combination.

Choose well supported terrain without convexities.Avoid shallow snowpack areas where triggering is more likely.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

2 - 3

Deep Persistent Slabs

Large triggers have produced big avalanches on this layer, down ~2m. It remains on our watch list and it's another reason to avoid shallow snowpack areas.

Be aware of the potential for large, deep avalanches due to the presence of buried surface hoar.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely

Expected Size

2 - 4

Valid until: Mar 23rd, 2014 8:00AM