Avalanche Forecast

Issued: Mar 16th, 2016 8:11AM

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

ian gale, Parks Canada

Glacier.

A 30 cm storm slab exists in the alpine and at treeline. This slab will become reactive quickly with even brief solar warming this afternoon.

Summary

Weather Forecast

Alpine temps will remain cool with freezing level up to 1200m, an alpine high of -6 deg with skies clearing in the afternoon. 3 cm of new snow is forecasted today with potential for more with isolated convective flurries. Ridge top winds will be westerly 20kph gusting 50 today and the relatively cool temps are expected to persist to the weekend.

Snowpack Summary

SW winds have created soft windslab on Alpine lee features & crossloads. Convective flurries have built a 30cm storm slab in the Alp & at TL which is reactive on a crust on specific terrain features. Feb 27th layer is down 70cm & reactive on solar slopes. Cornices are large, fragile and failing

Avalanche Summary

A 25cm storm slab has been catching riders off guard. There has been 4 reports of avalanches on this layer in the Connaught & Hermit areas. The largest was 20cm deep, 70m wide and ran 50m to a bench. The storm slab is poorly bonded to a crust and most reactive in unsupported terrain. Forecasters observed five sz 2's from steep terrain yesterday

Confidence

Problems

Storm Slabs

Convective flurries have created a 30cm storm slab. It is most reactive where it sits on a crust. This slab is catching riders off guard and is easily triggered on convex rolls. When the sun comes out this afternoon this slab will be very reactive!

Choose well supported terrain without convexities.Avoid exposure to terrain traps where the consequences of a small avalanche could be serious.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 3

Wind Slabs

Windslabs are widespread in the upper alpine and continue to be reactive to human triggering given the right terrain feature. Ripe cornices have been failing over the past several days. Avoid exposure to this overhead hazard.

Give cornices a wide berth when traveling on ridges.Use caution in lee areas. Recent wind loading has created wind slabs.

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Possible - Likely

Expected Size

1 - 3

Persistent Slabs

Feb 27 interface is down 80cm+ and continues to give sudden planar results in field tests. The layer consists of crusts on solar aspects and decomposing surface hoar in isolated locations.

Avoid steep convexities or areas with a thin or variable snowpack.Minimize exposure to steep, planer south facing Alpine slopes

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 3

Valid until: Mar 17th, 2016 8:00AM