Archived

Avalanche Forecast

Apr 27th, 2019–Apr 28th, 2019

Alpine

3: Considerable

The avalanche danger rating in the alpine will be considerable

Treeline

2: Moderate

The avalanche danger rating at treeline will be moderate

Below Treeline

2: Moderate

The avalanche danger rating below treeline will be moderate

Alpine

2: Moderate

The avalanche danger rating in the alpine will be moderate

Treeline

2: Moderate

The avalanche danger rating at treeline will be moderate

Below Treeline

1: Low

The avalanche danger rating below treeline will be low

Alpine

2: Moderate

The avalanche danger rating in the alpine will be moderate

Treeline

2: Moderate

The avalanche danger rating at treeline will be moderate

Below Treeline

1: Low

The avalanche danger rating below treeline will be low

Regions: Jasper.

A strong upslope storm has delivered heavy snowfall to the East and built windslabs in unusual places.

Weather Forecast

The low pressure center that drove Saturdays upslope moves into the prairies allowing cool air from the North East to establish itself over our area.

Sunday: Clear periods in the AM, with increasing cloud and flurries in the PM. Treeline temperature: Low -11 C, High -6 C. Ridge wind light northeast (gusting moderate). Freezing level: 1500 metres.

Snowpack Summary

A strong upslope has delivered over 30cm of snow in the front ranges, and up to 20cm in the Icefields region. This new snow is being reverse loaded by NE winds and will overly several crusts/facet layers in the upper snowpack. Windslabs can be expected on most aspects in the alpine. A faceted layer midpack on shady alpine aspects remains a concern.

Avalanche Summary

Poor visibility today, expect an avalanche cycle is ongoing with heavy loading from new snow and wind.

Confidence

Due to the number and quality of field observations

Avalanche Problems

Wind Slabs

Strong winds and heavy snowfall (heaviest in the front ranges) has built fresh slabs on most aspects. Be particularly cautious on planar slopes where the new snow overlies a crust.

Keep an eye out for reverse loading created by N-NE winds.
Use caution in lee areas. Recent wind loading has created wind slabs.

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Possible - Likely

Expected Size: 1 - 2.5

Persistent Slabs

Loading from new snow has likely increased the sensitivity of this layer.

Watch for signs of instability such as recent avalanche activity, and whumpfing/cracking underfoot.
If triggered the wind slabs may step down to deeper layers resulting in large avalanches.

Aspects: North, North East, East, North West.

Elevations: Alpine.

Likelihood: Possible

Expected Size: 1.5 - 3