Avalanche Forecast

Issued: Mar 11th, 2017 4:00PM

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

deryl kelly, Parks Canada

Jasper.

Safe, excellent riding conditions can be found in conservative terrain.

Summary

Weather Forecast

Light flurries will continue through the region, tapering off Sunday evening and into Monday. Temperatures will hold steady, with daytime highs near zero, especially in the northern end of the forecast region. Steady light to moderate southerly winds to continue.

Snowpack Summary

Moderate southerly winds transporting and pressing recent HST into soft slab and wind slabs 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 that is just supportive enough for travel below treeline. Deep persistent weakness of facets and depth hoar at the base.

Avalanche Summary

Road patrol on the Icefields Parkway observed no new avalanches. Poor visibility at treeline and above. Late report from the Ascend split-board festival group of a rider remote from a treeline location into the alpine. Two size 2 to 2.5 Sr(300) 100 to 150cm thick x 35m wide, running to bottom of the path.

Confidence

Problems

Wind Slabs

S-ly winds are creating slab on lee aspects and firming it up on windward aspects. Trigger and you're very likely to initiate deeper instabilities and really wreak your day.

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

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 3

Persistent Slabs

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

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

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

2 - 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.

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

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

2 - 4

Valid until: Mar 12th, 2017 5:00PM