Avalanche Forecast

Issued: May 3rd, 2014 4:00PM

The alpine rating is moderate, the treeline rating is moderate, and the below treeline rating is moderate. Known problems include Loose Dry, Wind Slabs and Deep Persistent Slabs.

conrad janzen, Parks Canada

Banff Yoho Kootenay.

Cool temperatures and up to 45cm of new snow have brought a brief return to winter conditions. Use caution in steep terrain and be aware that the new snow may hide a very weak, rain saturated base especially in thin areas.

Summary

Weather Forecast

Continued cool temps overnight with lows of -7'C and an additional 5cm of snow and light winds. Sunday we expect another 10cm of snow with alpine temperatures between -4'C and -1'C and light winds. Monday and Tuesday are a mix of sun and cloud, continued cool alpine temperatures and a trace of new snow. Freezing levels remain near the 2000m level.

Snowpack Summary

Soft slabs forming at tree line with light winds. 30-45cm of new snow overnight at tree line is generally bonding well to the moist snow beneath it. Moderate shears were present in the moist snow layer. The basal facets remain a concern, especially in thin areas where the lower snowpack is completely saturated with the recent rainfall.

Avalanche Summary

Sluffing out of steep terrain up to size 1 today. Local ski patrollers were able to ski cut small wind loaded pockets up to size 1.5. Two size 2 skier accidental avalanches occurred in thin areas near the Lake Louise ski area today with failures to ground in moist facets. Minimal natural activity was observed however visibility was limited.

Confidence

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

Problems

Loose Dry

Will all the new snow you can expect sluffing in steep terrain and gully features over the next 24hours.

Avoid travelling under cliffs that are exposed to sluffing from above.Sluffs may trigger deeper instabilities.

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 2

Wind Slabs

Light winds are forming soft slabs near ridge crests at tree line and above. So far the new snow seems to be bonding well to the moist snow below it however it would be wise to tread cautiously until things have a chance to settle out a bit more.

Avoid freshly wind loaded features.The new snow will require several days to settle and stabilize.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Deep Persistent Slabs

The deep facets continue to produce skier triggered avalanches in thin areas where the snow is saturated with the recent rain fall and very weak. Avoid steep thin areas until the wet snow has a chance to cool down and freeze.

Be aware of thin areas that may propogate to deeper instabilites.Avoid all avalanche terrain during periods of heavy loading from new snow, wind, or rain.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

2 - 3

Valid until: May 4th, 2014 4:00PM