Avalanche Forecast

Issued: Feb 21st, 2019 4:06PM

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

mconlan, Avalanche Canada

South Rockies.

Riders can still trigger persistent weak layers at lower elevations. Terrain like cutblocks, steep forest openings, and gullies are suspect. Wind slabs are the primary concern at higher elevations.

Summary

Confidence

Moderate - Due to the number of field observations

Weather Forecast

THURSDAY NIGHT: Partly cloudy, moderate west wind, alpine temperature -15 C.FRIDAY: Cloudy with light snowfall, accumulation 1 to 3 cm, moderate to strong southwest wind, alpine temperature -14 C.SATURDAY: Cloudy with light snowfall, accumulation 2 to 5 cm, light southeast wind, alpine temperature -18 C.SUNDAY: Partly cloudy, light northeast wind, alpine temperature -21 C.

Avalanche Summary

No new avalanches were observed in the region on Wednesday.

Snowpack Summary

Wind slabs exist in open, exposed areas at higher elevations. They may be found on all aspects due to variable wind directions. In sheltered terrain, around 20 to 30 cm of recent soft snowfall may be found.The mid-January weak layer of surface hoar or faceted grains is buried around 50 to 80 cm. It is found on shaded and sheltered slopes and is most prominent between 1600 m and 1900 m but has been found up to 2200 m. It may overly a melt-freeze crust on south aspects. Snowpack test results suggest that this layer may still be triggered by humans.The middle of the snowpack is generally consolidated. The bottom half of the snowpack is unconsolidated and composed of weak and sugary faceted grains. There is potential for shallower avalanches to step down to these deeper weak layers.

Problems

Wind Slabs

Use added caution in lee terrain features near ridges, as winds have formed stiff deposits. All aspects are suspect due to wind from variable directions.

Keep an eye out for reverse loading created by variable winds.If triggered, wind slabs may step down to deeper layers resulting in large avalanches.Use caution in freshly wind-loaded features, especially near ridge crests and in steep terrain.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Persistent Slabs

A weak layer of surface hoar is buried around 50 to 80 cm, which is best preserved in shaded and sheltered areas between 1600 m and 1900 m.

Be aware of the potential for wide propagation.Use added caution in open terrain features such as cutblocks, gullies and cutbanks.

Aspects: All aspects.

Elevations: Treeline, Below Treeline.

Likelihood

Possible

Expected Size

1.5 - 2.5

Valid until: Feb 22nd, 2019 2:00PM