Avalanche Forecast

Issued: Apr 23rd, 2017 4:00PM

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

Garth Lemke, Parks Canada

Jasper.

Monday afternoon or evening may bring 12-15mm of precipitation. This will be rain at low elevations and 10-20cm snow in higher elevations. The avalanche danger may reach 'Considerable' levels as a result yet weather models are uncertain.

Summary

Weather Forecast

Weather models are not agreeing as to precipitation amounts or its timing. "Sometime" Monday afternoon or evening may bring 10-20cm of snow and showers below 2200m. Tuesday and Wednesday may or may not be sun. The larger satellite image shows a series of Spring storms rolling into BC which may influence clouds and precipitation in our domain.

Snowpack Summary

10-20 cm snow Thursday night and a little more Saturday night has improved skiing yet it rests on a crust on solar aspects. The upper snowpack is moist or wet by the afternoon. The solid mid-pack bridges the weak base. The bottom 30cm of the snowpack is weak facets and depth hoar. Below 1500m there is no snow.

Avalanche Summary

No new avalanches noted in Maligne valley on Sunday. Numerous loose wet point and wet slab avalanches size 1.5 to 3 on West aspects noted in Icefields on Sunday likely triggered by rapid warming when the sun poked through the clouds.

Confidence

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

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.

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, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Wet Slabs

Recent snow, variable winds, and warm temperatures have created wet slab on a pre-existing slippery crust up to 2500m on West aspects. Natural activity of this character noted Sunday in Icefields triggered by rapid warming and sun.

Use extra caution on solar slopes or if the snow is moist or wet.Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet.

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

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.

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

Valid until: Apr 24th, 2017 4:00PM