Avalanche Forecast

Issued: Mar 20th, 2018 4:05PM

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.

rupert wedgwood, Parks Canada

Jasper.

Be mindful of solar radiation, even on partly cloudy days.

Summary

Weather Forecast

Chance of an upslope storm on Thur evening with warmer temps and winds from the SE. Tonight freezing level to valley bottom. Wednesday cloudy with sunny periods and isolated flurries. Freezing level: 1800 m. Alpine high -1 C. Ridge wind south: 10-25 km/h. Warmer on Thursday with up to up to 10cm overnight and into Friday.

Snowpack Summary

10-15cm of dense snow with moderate winds this week has created windslabs in lee features treeline and above. These windslabs are reactive on cooler, shaded aspects where they formed on a faceted surface. Loose wet slides are occurring below treeline in the late afternoon (particularly with direct sun) due to an increasingly isothermal snowpack.

Avalanche Summary

Road patrol Tuesday noted loose wet avalanches to size one below treeline. An isolated loose, dry avalanche that ran size 2 was observed from steep terrain at 2400m on a shaded aspect near Parker Ridge and 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.

Best conditions on sheltered northerly aspects.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2.5

Loose Wet

Watch for snowpack to become reactive if the sun comes out.

Minimize exposure to steep, sun exposed slopes when the solar radiation is strong.Avoid ice climbs exposed to steep rocky terrain on solar aspects during the middle of the day.

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

Elevations: Alpine.

Likelihood

Unlikely - Possible

Expected Size

1 - 1.5

Valid until: Mar 21st, 2018 4:00PM