Avalanche Forecast

Issued: Apr 15th, 2019 4:00PM

The alpine rating is moderate, the treeline rating is low, and the below treeline rating is low. Known problems include Loose Dry, Persistent Slabs and Wind Slabs.

Rupert wedgwood, Parks Canada

Jasper.

Summary

Weather Forecast

A cool and unstable air mass over the region giving isolated flurries in the alpine for the start of the week. Freezing levels rise towards the end of the week. On Tue a mix of sun and cloud with alp highs of -3C and freezing levels close to 2000m. A system starts to move in on Wed with increasing gusting winds from the SW then snow on Thursday.

Snowpack Summary

Above treeline 10cm of loose snow sits on a variety of crusts. Above 2200m, on Northerly facing slopes, a more winter like snowpack can be found. However, at and below 2200 melt-freeze crust dominate the upper snowpack. In the alpine a weak layer down 20-50cm is of concern. Mid and lower snowpack is faceted, and weak in shallow areas.

Avalanche Summary

Recent observation confirm only small loose dry releases from steep and rocky north facing terrain and gully features. Whumphing has been noted from shallower snowpack areas and moraine features indicating unstable snow below.

Confidence

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

Problems

Loose Dry

These small events have been noted from steep alpine terrain where climbers may frequent.

Be very cautious with gully features.Avoid travelling on ledges and cliffs where sluffing may have severe consequences.

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 1.5

Persistent Slabs

Evidence from recent snowpack tests and whumphing would suggest that a weak layer of facets persists down 20-50cm in some areas, and may be becoming reactive with incremental loading from recent small snowfalls or forecasted snow in the week ahead.

Avoid shallow snowpack areas where triggering is more likely.Avoid cross loaded features.

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

Elevations: Alpine.

Likelihood

Unlikely - Possible

Expected Size

1 - 2

Wind Slabs

On going convective snow flurries will produce sufficient snow to create isolated pockets of windslab. Significant snow events forecasted for late Thursday and Friday will reactivate these formations and create new storm slabs.

Be careful with wind loaded pockets, especially near ridge crests and roll-overs.

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

Elevations: Alpine.

Likelihood

Unlikely - Possible

Expected Size

1 - 2

Valid until: Apr 16th, 2019 4:00PM