Avalanche Forecast

Issued: Feb 4th, 2016 7:41AM

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

esharp, Avalanche Canada

Purcells.

There have been a few recent close calls in the north of the region near Golden where very large human-triggered avalanches have been reported in the last week. Conservative terrain selection remains critical.

Summary

Confidence

Moderate

Weather Forecast

FRIDAY: 5cm new snow through the day, moderate to strong southerly winds, freezing level rising to 1300m. SATURDAY: up to 10cm overnight with lingering flurries through the day, moderate westerly winds, freezing level of around 1000m. SUNDAY: flurries, light westerly winds, freezing level returning to valley floor overnight before rising to 1300m through the day.

Avalanche Summary

On Tuesday a skier triggered a size 2 wind slab near Panorama but was able to escape without being buried. On Monday, a size 2 wind slab was accidentally triggered by a skier in the backcountry around Golden. On Saturday a size 3 sledder-triggered avalanche occurred in the Gorman Creek riding area near Golden. The early January interface is the suspected weak layer. Around the same time, a size 3.5 skier-triggered persistent slab avalanche occurred a few drainages to the south of Gorman Creek on a north-facing alpine slope. Destructive persistent slabs are expected to remain reactive to human triggering for the forecast period.

Snowpack Summary

Up to 30cm of snow has fallen in the last week, and resulting wind slabs continue to be sensitive to light inputs in upper elevation lee terrain. The persistent weak layer of surface hoar and facets buried in early January is now typically down 60-90 cm. The layer is slowly getting harder to human trigger in many areas, however, reports of whumpfing and recent large to very large avalanches around Golden indicate this layer is still very much a concern in the north of the region. In general, the lower snowpack below this layer is well settled and strong.

Problems

Persistent Slabs

Low probability high consequence conditions persist, especially in the Dogtooth Range near Golden. A few close calls serve as a warning this layer can surprise with nasty consequences.

Be aware of the potential for remote triggers and wide propagations due to a layer of buried surface hoar and facets. >Be cautious around open slopes and convex rolls at and below treeline where buried surface hoar may be preserved.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

3 - 5

Wind Slabs

Fresh wind slabs are lurking below ridge crests and behind cross-loaded terrain features. Cornices have also been reported to be large and fragile.

Be cautious as you transition into wind affected terrain. >Use ridges or ribs to avoid pockets of wind loaded snow. >Avoid freshly wind loaded features. >

Aspects: North, North East, East, South East, South.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 3

Valid until: Feb 5th, 2016 2:00PM