Avalanche Forecast

Issued: Feb 25th, 2016 4:00PM

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

garth lemke, Parks Canada

Jasper.

Danger has the potential to increase with intense sun and warm temperatures at all elevations especially on solar aspects.

Summary

Weather Forecast

Friday freezing level will rise to 2000m by mid-afternoon with sunny skies. Expect -11 overnight to +3 during the day and much warmer in the sun. A weak temperature inversion may form Friday. Light westerly will dominate the next few days and potentially 2-5 cm of new snow Saturday.

Snowpack Summary

Approximately 20cms of soft surface snow in sheltered locations at TL over a supportive mid-pack. This is sitting on a weak basil facet layer. The HS BTL is more inconsistent in depth and support. Solar aspects have a thin sun crust down 20cms and producing moderate to hard resistant compression test results. Sun is creating surface crusts.

Avalanche Summary

No field trip Thursday. Tuesday observed two new avalanches above the Maligne road which appeared to be solar triggered. Some cornice failures also noted in Icefields area which triggered the basal weakness.

Confidence

Freezing levels are uncertain on Friday

Problems

Wind Slabs

Wind slabs are bonding well, however caution is still warranted in immediate lees and cross loaded terrain above treeline.

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

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

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

1 - 2

Persistent Slabs

Persistent weak layers of decomposed surface hoar, facets, and depth hoar are in many locations. These layers have been stubborn to trigger underfoot but could trigger with a cornice failure or from shallow spot.

Avoid steep slopes below cornices.Carefully evaluate terrain features by digging and testing on adjacent, safe slopes.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 3

Loose Wet

Loose wet avalanches, especially in the later afternoon with warm sunny skies, are possible on south and westerly aspects. Probability increases with sun.

Minimize exposure to steep, sun exposed slopes when the solar radiation is strong.

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 3

Valid until: Feb 26th, 2016 4:00PM