Avalanche Forecast
Issued: Mar 22nd, 2020 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Persistent Slabs.
ahanna,
Avalanche Canada
In areas where more than 20 cm of new snow has accumulated, watch for small loose dry avalanches and isolated pockets of thin but potentially reactive storm slab. An underlying crust makes a great bed surface and avalanches may run surprisingly far.
Summary
Confidence
Weather Forecast
Sunday night: Up to 5 cm new snow. Light northeast to southeast wind. Freezing level 600 m.
Monday: Flurries. Light northeast wind. Freezing level 900 m.
Tuesday: Up to 5 cm new snow then clearing. Moderate northeast wind. Freezing level 700 m.
Wednesday: Clear. Moderate northwest wind. Freezing level 1000 m.
Avalanche Summary
Loose wet avalanches were observed on solar aspects during the warm, sunny week. A few cornice failures were also observed but did not trigger slabs. Glide slab activity has been reported recently out of steep terrain where snow sits over smooth surfaces.
If you decide to travel in the backcountry, consider sharing your observations with us and fellow recreationists via the Mountain Information Network (MIN) to supplement our data stream as operators are shutting down. Even just a photo of what the day looked like would be helpful.
Snowpack Summary
Up to 25 cm of new snow sits over melt-freeze crusts on solar aspects, and extensively wind affected surfaces in exposed terrain that did not see the sun.
A layer of surface hoar crystals is buried around 30-60 cm in sheltered areas at and below treeline. See this MIN from the Shames area that shows this layer when it was on the surface, prior to burial on March 9.
An early-season layer of faceted grains and a melt-freeze crust may linger at the base of the snowpack. A large load, such as a cornice fall, has the potential of triggering it.
Terrain and Travel
- Closely monitor how the new snow is bonding to the crust.
- Keep in mind the crust offers an excellent bed surface for avalanches.
- Carefully assess open slopes and convex rolls where buried surface hoar may be preserved.
Problems
Persistent Slabs
A weak layer of surface hoar crystals is buried around 30 to 60 cm in sheltered, shady terrain around treeline. It was previously reactive to both human and natural triggers. Recent warm temperatures have likely promoted bonding of this layer and there is uncertainty around whether it is still sensitive to triggering.
Aspects: North, North East, East, West, North West.
Elevations: Treeline.
Likelihood
Expected Size
Valid until: Mar 23rd, 2020 5:00PM
