Avalanche Forecast

Issued: Mar 27th, 2016 4:00PM

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

garth lemke, Parks Canada

Jasper.

http://www.pc.gc.ca/apps/scond/Cond_E.asp?oID=23025&oPark=100244The persistent slab will be with us for sometime. Adjust your spring skiing strategy accordingly. Despite the moderate rating, there is a low probability of triggering but a high consequence if your wrong. Spatial variability adds to the complexity.

Summary

Weather Forecast

Expect 5-10cm Sunday night with -10 Celsius. Monday will be freezing levels of 1500-2000m depending on cloud cover. Could be colder temperatures Monday night as a Northerly wind dominates. Tuesday-Wednesday daytime temperatures may spike up to 2300m with less overnight recovery. This depends on cloud cover. No snow expected. Sun Thursday-Friday.

Snowpack Summary

The snowpack is settling into spring like conditions at TL and BTL on solar aspects. Good overnight recovery with temps to -10 and rising 0 in the alpine by midday. Significant variation in snowpack depth through-out the forecast area with a large proportion being shallow and valley bottoms below 1800m in spring bloom. Basal depth hoar exists.

Avalanche Summary

No field patrol Sunday. Several loose wet slides on solar aspects in the south end of the park likely occurred on Friday when temperatures were higher. Saturday observationed a sz 2.5 on a SW'ly aspect near the Boundary. Large serac collapse on the north glacier of Mt. Athabasca. Cornice failure noted in Marmot Basin backcountry.

Confidence

Freezing levels are uncertain on Tuesday

Problems

Persistent Slabs

This problem has been most active in the Whistler/Portal Creek area but is widespread through the forecast region. When triggered, it will be big with serious consequences. Warm and sunny conditions will increase this danger.

Minimize exposure to overhead avalanche terrain, large avalanches may reach run out zones.Be aware of thin areas that may propogate to deeper instabilites.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 3

Cornices

Some cornice failures are being noted. It can act as a large trigger initiating deep weaknesses plus their sheer mass, whether or not it initiates an avalanche, would be like being hit by a car.

Minimize exposure to overhead avalanche terrain, large avalanches may reach run out zones.Avoid slopes when the solar radiation is strong, especially if they have large cornices overhead.

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

Elevations: Alpine.

Likelihood

Unlikely - Possible

Expected Size

1 - 2

Loose Wet

This problem is unlikely on Monday but will become significant later in the week with forecasted warm temps and intense solar radiation. The danger rating will rapidly increase on thin solar slopes

Avoid ice climbs that are exposed to steep rocky terrain on solar aspects.Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet.

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

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

1 - 2

Valid until: Mar 28th, 2016 4:00PM