Avalanche Forecast

Issued: Apr 9th, 2013 8:10AM

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

ali haeri, Parks Canada

Glacier.

Summary

Weather Forecast

Weak high pressure ridge being pushed out by a strong pacific frontal system by late this afternoon. Expect increasing cloud cover and rising freezing levels. Precipitation amounts forecast for this storm are variable, between 15 and 30mm by Wednesday night. Unsettled weather and light precipitation will linger on Thursday.

Snowpack Summary

Variable snow conditions in upper snowpack elevation dependant. 10-15cm firm crust on the surface below treeline over moist snow. Top 10cm is wind affected at treeline and alpine elevations. Profile at 2090m, SE aspect, 36 degrees showed easy, sudden planar test results down 9cm on surface hoar and moderate results down 25cm below a 15cm crust.

Avalanche Summary

Yesterday: 4 natural slab avalanches, all size 2.0, east of the Rogers Pass summit on north facing terrain. From 2 days ago, size 3.0 natural slab avalanche in Youngs Peak Basin and a skier triggered size 2.0 off of Youngs Peak Headwall.

Confidence

Intensity of incoming weather systems is uncertain on Wednesday

Problems

Wind Slabs

Wind slabs have been observed at upper elevations and may catch a rider off guard. N-NE winds have prevailed in the last 48hrs loading slopes that are typically on the windward side.

Be cautious as you transition into wind affected terrain.

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 2

Deep Persistent Slabs

Glide cracks, gaping cracks in the snowpack, exist on many slopes and have been failing with the warm temps. They can fail unpredictably and release the entire snowpack to the ground.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 4

Persistent Slabs

Buried crusts and surface hoar layers in the upper meter of the snowpack may be reactive to rider triggering from shallow areas where the snowpack is weak.

Be aware of thin areas that may propogate to deeper instabilites.Avoid shallow snowpack areas where triggering is more likely.

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Unlikely

Expected Size

2 - 3

Valid until: Apr 10th, 2013 8:00AM