Avalanche Forecast
Issued: Mar 13th, 2020 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs and Deep Persistent Slabs.
Tim Haggarty,
Parks Canada
North winds have redistributed recent snow and are creating wind slabs in some unusual locations. Stay warm out there.
Summary
Weather Forecast
The arctic push is on with moderate North winds in the alpine and Eastern gap winds moving through the valleys that will persist through to Sunday. Cold air has flooded the region and -30C is expected overnight Friday in the alpine before some improvement Saturday afternoon .Expect winds to increase to strong in the alpine.
Snowpack Summary
15-25cm of snow over the last 3 days has been redistributed by moderate winds of variable direction at treeline and above creating wind slabs in open areas. On steep solar a thin crust has formed on the surface. We continue to monitor the deep, weak facetted snow in the shallower areas of the park.
Avalanche Summary
Direct observation of a natural size 3 cornice release from the postcard face on Cascade mountain Wednesday. The avalanche ran 1700m to the top of the run out zone. Another size 2 wind slab was observed from the last 24 hours on a S facing slope at 2300m on Observation Peak. Some sluffing has been observed in steep terrain.
Confidence
Wind speed and direction is uncertain on Saturday
Problems
Wind Slabs
Recent snow and west winds had developed stubborn slabs at ridge crest however Thursday evening winds shifted to the N and E and are expected to increase Saturday. Expect a different loading pattern than is usual.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Deep Persistent Slabs
Use caution in thin snowpack areas averaging 150cm or less. In these areas, the basal snowpack consisting of depth hoar and facets remains weak and the overlying mid and upper snowpacks are thin enough to allow for triggering.
- Pay attention to overhead hazards like cornices which could trigger the deep persistent slab.
- Be aware of thin areas that may propogate to deeper instabilites.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Mar 14th, 2020 4:00PM
