Avalanche Forecast

Issued: Feb 2nd, 2016 8:42AM

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.

jlammers, Avalanche Canada

Purcells.

There have been a few recent close calls in the north of the region near Golden. Very large human-triggered avalanches have been reported over the past few days. Conservative terrain selection remains critical.

Summary

Confidence

Moderate

Weather Forecast

On Wednesday evening, the first of 2 organized fronts will move through the region bringing 3-5cm of new snow and strong southwest winds. Thursday will see mainly overcast skies and continued strong ridgetop winds. By Friday evening, the second front will pass through the region. Expect another 5-10cm of snow and strong southwest winds. Freezing levels should remain at valley bottom for Wednesday and Thursday, and then rise to about 1500m for Friday.

Avalanche Summary

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. According to the report, 4 people were involved in the incident; however, all of the party member survived. Hats off to the sledders who responded to the incident in a calm and organized manner. Check-out the great Mountain Information Network report for details. 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. Nobody was injured in the event. On Monday, a size 2 wind slab was accidentally triggered by a skier in the backcountry around Golden. The individual was carried to the bottom of the slope, but was not buried or injured. Destructive persistent slabs are expected to remain reactive to human triggering for the forecast period.

Snowpack Summary

30-60cm of snow fell 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 in the Golden area 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

The likelihood of triggering buried surface hoar and facets is slowly dropping in many areas, but touchy conditions persist 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 - Likely

Expected Size

3 - 5

Wind Slabs

Recently formed wind slabs are lurking below ridge crests and behind cross-loaded terrain features and may remain sensitive to human triggers. 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

Possible

Expected Size

1 - 3

Valid until: Feb 3rd, 2016 2:00PM