Avalanche Forecast

Issued: Apr 8th, 2014 4:00PM

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

rupert wedgwood, Parks Canada

Jasper.

Mild temperatures, rain and strong winds are decreasing the snowpack stability. Several large avalanches from treeline and below occurred on Tuesday near the Columbia Icefields.

Summary

Weather Forecast

Cooling temperatures over the next 48 hours with the chance of snow flurries. The SW flow will become more westerly with the freezing levels dropping to the valley bottom overnight and not reaching the treeline during the day. Cooler temperatures are forecast for the Icefields area where the greater amounts of snow can also be expected at elevation

Snowpack Summary

At treeline and below warming temperatures and rain has increasing the temperature of the snowpack. Moist snow in the upper pack can be anticipated. Surface crusts will form when temps drop. Solar facing slopes close to treeline may have buried crusts with slab snow above. Deeply buried weaknesses near ground. Windslabs in the alpine.

Avalanche Summary

Slab and point release avalanches observed Tuesday up to size 2.5 from treeline and below. All events are stepping to ground. Most are being triggered by warm temperatures and rain. One or two of these events started above treeline in areas where strong and extreme winds, from the SW, are developing wind slabs. These to are steeping down to ground.

Confidence

Freezing levels are uncertain on Wednesday

Problems

Wet Slabs

With cooling temperatures this condition will stabilize. Rain and solar exposure will increase the danger. Weather conditions will be variable across the region. Snowballing and pin wheels should be regarded as signs of deteriorating conditions.

Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet.Avoid shallow snowpack areas where triggering is more likely.

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

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

2 - 3

Deep Persistent Slabs

Continued wind loading and warming temperatures have increased the triggering sensitivity of this weakness. Strong SW winds on Tuesday were present across the region but most noticeable in the Columbia Icefields area

Avoid shallow snowpack areas where triggering is more likely.Watch for clues, like sluffing off of cliffs, that the snowpack is warming up.

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

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

2 - 3

Wind Slabs

Strong SW winds on Tuesday have created slab conditions. SE aspects where buried sun crusts may provide a sliding surface should be approached with caution. Thin slabs will likely step down to the basal weaknesses near ground producing large slides.

Use caution in lee areas. Recent wind loading have created wind slabs.If triggered the wind slabs may step down to deeper layers resulting in large avalanches.

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 3

Valid until: Apr 9th, 2014 4:00PM