Avalanche Forecast

Issued: Mar 12th, 2017 4:00PM

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

garth lemke, Parks Canada

Jasper.

Safe, excellent riding conditions can be found in conservative terrain. Watch for changing conditions next few days if day time temperatures warm more than they are forecasted.

Summary

Weather Forecast

30-40km/hr SW winds around the townsite Monday, +9 and flurries. Icefields will be -3 to -6 Monday to Tuesday with potentially spiking warm temperatures on Wednesday. Flurries will continue Monday to Wednesday being possible rain on Wednesday. Winds will be steady 20-30km/hr out of SW.

Snowpack Summary

Light to Moderate southerly winds transporting and pressing recent snow into a slab in open areas at TL and above. This sits on a persistently weak interface 20 to 45cm down. A weak but slowly improving mid-pack is just supportive enough for travel below treeline. Basal layer of weak facets, depth hoar, and an ice crust from November.

Avalanche Summary

Sunday's Maligne patrol observed no new avalanches. Saturday's Icefield's patrol observed no new avalanches but it was poor visibility. March 11 report from skiers of a remotely triggering from a treeline location 300m into the alpine two size 2.5's 1.5m thick and 35m wide. They ran to bottom of the path.

Confidence

Freezing levels are uncertain

Problems

Wind Slabs

SW winds creating slabs on lee and pressing snow on windward aspects. May be overtop decomposed SH layer on CR 30cm down on South TL aspects.

Minimize overhead exposure during periods of heavy loading from new snow, wind.If triggered the wind slabs may step down to deeper layers resulting in large avalanches.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 3

Deep Persistent Slabs

Natural activity has subsided but don't let your guard down. It remains a major concern with a extremely weak base of depth hoar. Trigger spots would be shallow zones or a step down effect if upper layers are initiated.

Avoid shallow snowpack areas where triggering is more likely.Use conservative route selection, choose moderate angled and supported terrain with low consequence.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

2 - 4

Persistent Slabs

Persistent mid-pack slab condition continuing to surprise but not the good kind of surprise! Like triggering an unseen overhead feature; Surprise!

Avoid exposure to overhead avalanche terrain, large avalanches may reach the end of run out zones.Watch for whumpfing, hollow sounds, and shooting cracks.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

2 - 3

Valid until: Mar 13th, 2017 4:00PM