Avalanche Forecast
Issued: Mar 13th, 2020 8:21AM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Storm Slabs and Persistent Slabs.
mike smallwood,
Parks Canada
Storm slabs are reactive to mountain travelers. The persistent weak layer, if triggered has the potential to propagate into large avalanches
Summary
Weather Forecast
Flurries are forecast throughout the day today with light reverse winds from the east/northeast bringing decreasing temperatures to a low of -20 by the afternoon. Cold temperatures will persist through Saturday with clearing skies and continued light wind. Warming up on Sunday and clearing.
Snowpack Summary
Up to 30cm of storm snow on Tues night, that came in with mod to strong SW wind, is now settling over the Mar 10 interface of surface hoar on shaded slopes and suncrust elsewhere. Below this slab the Feb 22 persistent weak layer is down 90-130cm and consists of 3-7mm surface hoar on all aspects up to 2450m and a crust on solar aspects.
Avalanche Summary
Wednesday's avalanche cycle produced natural avalanches to size 3 and controlled avalanches to size 3.5 in the highway corridor. The slides from avalanche control were mainly confined to the storm snow with Camp West path possibly digging deeper. Natural activity decreased yesterday but the storm snow is still reactive to skiers.
Confidence
Problems
Storm Slabs
30cm of recent snow with mod/strong winds has created a widespread storm slab. Unsupported slopes and terrain traps should be avoided. Lee and cross-loaded features will be more reactive due to the wind further promoting slab formation in these areas
- If triggered the storm slabs may step down to deeper layers resulting in large avalanches.
- The new snow will require several days to settle and stabilize.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Persistent Slabs
The February 22 surface hoar/sun crust layer is down 90-130cm. Skier-triggering is possible in shallower areas but otherwise this layer will take a bigger trigger to be activated such as a storm slab stepping down or large load impacting the slope.
- Be aware of the potential for wide propagations.
- Avoid steep convexities or areas with a thin or variable snowpack
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Mar 14th, 2020 8:00AM
