Avalanche Forecast

Issued: Apr 24th, 2017 4:00PM

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

deryl kelly, Parks Canada

Jasper.

Forecast reflects the highest hazard of the day, most often by early afternoon. New snow amounts vary through the forecast area!

Summary

Weather Forecast

Weather models still suggest that Monday evening could bring 10-20cm of snow and showers below 2200m. Short intense storms continue to move through the forecast area. Broken skies and light southerly winds for the day Tuesday, clearing overnight and into Wednesday.

Snowpack Summary

Recent HST has improved skiing significantly. New snow expected overnight Monday, variable amounts up to 15cm forecast for some locations. Spring continues to penetrate deeper into the upper snowpack, which is often saturated by the late afternoon. The solid mid-pack bridges the weak base. The bottom snowpack is mixed facets and depth hoar.

Avalanche Summary

No new avalanches noted or reported.

Confidence

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

Problems

Loose Wet

Warm temperatures and direct solar radiation influence the 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.

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

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

Elevations: Alpine, Treeline.

Likelihood

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.

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

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.

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

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 4

Valid until: Apr 25th, 2017 4:00PM