Avalanche Forecast

Issued: Apr 7th, 2013 8:02AM

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

catherine brown, Parks Canada

Glacier.

A variety of spring surface conditions will keep skiing interesting in the park today. Keep an eye out for spring hazards including cornices, glide cracks and loose, unconsolidated snow.

Summary

Weather Forecast

Broken cloud cover is forecast today with convective clouds and precipitation possible this afternoon. Wind are forecast to be light. Freezing levels will rise to around 1600 m with alpine temps remaining cool at -5. This weather will continue into Monday with temperatures remain cool as a ridge of high pressure builds in and remains on Tuesday.

Snowpack Summary

Cooler temperatures overnight will have frozen the surface snow. The surface condition will change rapidly today as freezing levels rise. An isothermal snowpack has been reported in some locations at treeline. These conditions result in a loose, unconsolidated snowpack. Precipitation that did fall as snow over the last few days will be heavy.

Avalanche Summary

We observed loose, moist/wet natural avalanche running in the highway corridor over the last few day. One notable event was a size 3, from a deep slab release at 1700 m. Glide cracks are still failing, up to size 2.5.Artillery avalanche control along the highway corridor on Friday produced numerous size 2-2.5 loose, moist avalanches.

Confidence

Timing, track, or intensity of incoming weather system is uncertain on Tuesday

Problems

Loose Wet

Natural avalanches are possible with the current spring conditions. Avalanches that trigger on a shallow crust can dig deeper into the isothermal snow and get bigger. Use caution in terrain with loose unconsolidated snow.

Watch for terrain traps where small amounts of snow will acumulate into deep deposits.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Unlikely - Possible

Expected Size

2 - 3

Storm Slabs

Up to 20 cm of new snow in the alpine could be rider triggered. Watch for this snow to have formed a slab of denser snow. Use caution on lee features in open terrain.

The new snow will require several days to settle and stabilize.Watch for whumpfing, hollow sounds, shooting cracks or recent avalanches.

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 3

Cornices

Cornice are large on many ridgelines in the park. A cornice fall could trigger a slab avalanche. Minimize your exposure to this hazard, especially in the afternoon as temperature rise.

Cornices become weak with daytime heating, so travel early on exposed slopes.Avoid steep slopes below cornices.

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

Elevations: Alpine.

Likelihood

Unlikely - Possible

Expected Size

2 - 3

Valid until: Apr 8th, 2013 8:00AM