Avalanche Forecast

Issued: Mar 21st, 2018 4:00PM

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

jonas hoke, Parks Canada

Jasper.

Good skiing can be found on sheltered alpine slopes, but watch for wind loaded pockets as you transition off of ridge crests.

Summary

Weather Forecast

A complex pattern full of uncertainty. Lows from the Gulf of Alaska and costal Californian track east, converge and provide unsettled mild weather with precip. Thurs: Flurries (5cm). Alpine temps: Low -9C, High 1C. Ridge wind light to mod SE. Freezing level: 2100m.Fri: Flurries (up to 10cm). Alpine temps: Low -11C, High -3C. Light to mod SW wind.

Snowpack Summary

Moderate winds have redistribute last weeks 10-15cm of snow into windslabs in lee features at treeline and above. These windslabs are more reactive on cooler, shaded aspects where they formed on previously faceted surfaces. Loose wet slides remain a concern below treeline in the late afternoon due to an increasingly isothermal snowpack.

Avalanche Summary

A road patrol Tuesday noted loose wet avalanches to size one below treeline, and one isolated thin slab avalanche that ran size 2 from steep terrain at 2400m on a shaded aspect near Parker Ridge. On Tuesday a field team triggered a size 1.5 windslab avalanche on moderate terrain on Mt. Kitchener at 3100m (60m wide, 60m long, 20-40cm deep crown).

Confidence

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

Problems

Wind Slabs

Windslabs sit on a hard melt-freeze crust on solar aspects, and facets on polar aspects. Shaded slopes have been more reactive. Assess the bond at these interfaces carefully before committing to avalanche start zones.

The new snow will require several days to settle and stabilize.Be careful with wind loaded pockets, especially near ridge crests and roll-overs.

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2.5

Loose Wet

Rain will destabilize the snowpack turning it isothermal, particularly where the snow cover is thin.

Avoid travel above cliffs and in terrain traps, where small avalanches may have severe consequences.

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 1.5

Valid until: Mar 22nd, 2018 4:00PM