Avalanche Forecast

Issued: Apr 25th, 2017 4:00PM

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

garth lemke, Parks Canada

Jasper.

Skiing is good as new snow remains loose and unaffected by wind. Temperatures expected to stay cool next couple days so good time to get out there.

Summary

Weather Forecast

Tuesday night will be clear and -8 to -12 degrees. Wednesday will start clear but increasing cloud into the afternoon. Wednesday will be relatively cool at -2 to -4 and 1800m freezing level. This freezing level will maintain into Thursday with increasing cloud and potential for some more precipitation Thursday to Friday.

Snowpack Summary

20cm loose new snow sits overtop a melt freeze crust in many locations above tree line. Mid pack is consolidated and bridges the weak base. The bottom snowpack is mixed facets and depth hoar.

Avalanche Summary

Tuesday's Icefields patrol noted one size 3 slab 72 hours old on West aspect at 2500m. Some small solar point releases noted out of rocky areas.

Confidence

Timing or intensity of solar radiation is uncertain on Wednesday

Problems

Loose Wet

Warm temperatures and direct solar radiation influence its distribution and magnitude. Freezing overnight temperatures decrease the danger in the morning until it warms up increasing the hazard. Most widespread on solar facing slopes.

Minimize exposure to steep, sun exposed slopes when the solar radiation is strong.Start and finish early before the surface crusts melt.

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

Elevations: Alpine.

Likelihood

Unlikely - Possible

Expected Size

1 - 2

Cornices

Cornice failures are still being noted periodically on West aspects 2500-2800m. Give them a wide berth as their failure is hard to predict but increases with sun, warmth, wind-loading, or new snow.

Avoid travel on slopes that are exposed to cornices overhead.Give cornices a wide berth when travelling on or below ridges.

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

2 - 3

Deep Persistent Slabs

The deep instability could be triggered by a cornice failure. It is well bridged by a solid mid-pack; however, consider this problem becoming more active particularly on South aspects as the day warms up or the sun comes out.

Minimize exposure to steep, sun exposed slopes when the solar radiation is strong.Pay attention to overhead hazards like cornices which could easily trigger the deep persistent slab.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 4

Valid until: Apr 26th, 2017 4:00PM