Avalanche Forecast

Issued: Apr 10th, 2017 7:59AM

The alpine rating is moderate, the treeline rating is moderate, and the below treeline rating is low. Known problems include Storm Slabs and Cornices.

chris gooliaff, Parks Canada

Glacier.

Sunshine and daytime warming will increase the likelihood of triggering surface storm slabs. It feels like Spring in the valley, but it is still full-on winter in the alpine.

Summary

Weather Forecast

A mix of sun and cloud today, with isolated flurries, alpine highs of -3*C, freezing levels rising to 1600m, and light westerly winds at ridge-top. Flurries tonight and another day of mixed sun and cloud with flurries on Tuesday.

Snowpack Summary

30cm of snow fell in the alpine over the weekend, while the amounts diminish to 10-15cm around 1800m. Winds were strong from the S, but backed off to light on Sunday. This new snow lies on a firm temp crust and is reactive to light loads, especially where loaded in lee features. Deep persistent weak layers have not been reactive with the cool temps

Avalanche Summary

No new avalanches were observed in the highway corridor nor up the Illecillewaet drainage yesterday. Artillery control from Saturday produced surface slabs mainly size 2, some to size 3. All slabs were from the storm snow and were not observed digging down into the deeper layers.

Confidence

Problems

Storm Slabs

New storm snow needs time to bond to the underlying firm temp crusts. Where winds have redistributed it in lee features, expect the slabs to be reactive to light human loads, especially at ridge-top, over convexities, and large planar alpine slopes.

Be careful with wind loaded pockets, especially near ridge crests and roll-overs.Minimize exposure to steep, sun exposed slopes when the solar radiation is strong.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 3

Cornices

Large cornices guard the high alpine ridges and are HUGE. If these fail, due to direct sun, human loading, or wind loading, they could dig down into the snowpack and trigger deep persistent slabs. Always keep an eye on the high alpine ridges.

Pay attention to overhead hazards like cornices which could easily trigger persistent slabs.Give cornices a wide berth when traveling on or below ridges.

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

Elevations: Alpine.

Likelihood

Unlikely - Possible

Expected Size

2 - 4

Valid until: Apr 11th, 2017 8:00AM