Avalanche Forecast

Issued: Apr 12th, 2017 4:00PM

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

deryl kelly, Parks Canada

Jasper.

Unsettled weather for the next few days in the Icefields area. Local precip and accumulation may vary wildly from region and elevation.

Summary

Weather Forecast

Light flurries continue to scatter through the forecast area. Models calling for light but consistent precip, heaviest overnight Thursday. Thus far it remains variable in both location and accumulation. Expect warm alpine temps near 0 with freezing levels rising to 1800m.

Snowpack Summary

Inconsistent support on a weak melt freeze crust, solar aspects. Dryer surface snow on polar aspects over a solid mid-pack bridging the weak base above 2000m. The base is a combination of weak facets and depth hoar mixed around a Nov rain crust. A consistent melt-freeze cycle is occurring below tree line.

Avalanche Summary

Field team reporting some observed loose wet slides and snow-balling BTL. Visibility poor and no ALP observations.

Confidence

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

Problems

Deep Persistent Slabs

The deep instability could be triggered by large loads such as a cornice failure or a surface avalanche. Human triggering is most likely from shallow spots or on steep unsupported slopes.

Pay attention to overhead hazards like cornices which could easily trigger the deep persistent slab.Be cautious in shallow snowpack areas where triggering is more likely.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 4

Cornices

Cornice failure is hard to predict but likelihood increases with sun, warm temperatures, and wind-loading.There are some very large cornices out there. Wise to give them a wide berth.

Pay attention to overhead hazards like cornices which could easily trigger the deep persistent slab.

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

Elevations: Alpine.

Likelihood

Unlikely - Possible

Expected Size

2 - 3

Loose Wet

Isothermal conditions are possible as crusts break down by late morning. Gauge the extent of the overnight freeze relative to how quick it will move into being reactive.

Minimize exposure to steep slopes on warm or sunny days.If triggered the loose wet sluffs may step down to deeper layers resulting in large avalanches.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

1 - 2

Valid until: Apr 13th, 2017 4:00PM