Avalanche Forecast

Issued: Feb 1st, 2018 3:45PM

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

Avalanche Canada shorton, Avalanche Canada

Stormy weather will elevate the danger this weekend. Minimize your exposure to avalanche terrain when there's rapid loading from new snow and wind.

Summary

Confidence

Moderate - Intensity of incoming weather systems is uncertain

Weather Forecast

FRIDAY: Snow with 10-20 cm Thursday night and another 10-20 cm on Friday / moderate southwest wind increasing to strong in the afternoon / alpine temperatures around -3 C.SATURDAY: Another 10-30 cm of snow / strong west wind / alpine temperatures around -3 C.SUNDAY: Another 10-30 cm of snow / strong west wind / alpine temperatures around -5 C.

Avalanche Summary

Evidence of natural activity from Tuesday's storm was observed on Wednesday. Avalanches included small to large storm slabs (size 1-2) and dry loose avalanches in steep terrain. In inland areas east of Terrace, a few natural avalanches released on the mid-January crust as well.A few size 1-2 persistent slab avalanches were also triggered by skiers on Wednesday, all of which failed on the mid-January crust which was roughly 60 cm deep. These occurred in the more inland areas east of Terrace and in northern parts of the region. The avalanches occurred on north alpine slopes and on a southwest treeline slope. The mid-January layer was also active in the Shames area last Saturday, where a skier triggered a size 2 avalanche on a northeast alpine slope. In this case, the weak layer was composed of surface hoar.Overall, activity on persistent weak layers was limited during this last storm, but enough to suggest it may remain reactive through this upcoming stormy period.

Snowpack Summary

Fresh snow will continue to accumulate the next few days. Areas around Terrace have already seen over 60 cm the past few days. Warm temperatures are promoting the settlement of new snow, while westerly winds are blowing snow around in exposed areas and forming touchy slabs.A weak layer buried in mid-January remains a concern and is now 60-100 cm deep. In most areas this layer is a crust, but it may also be surface hoar in sheltered areas at treeline and below. This layer has produced a few human triggered avalanches throughout the region over the past week, and may become more reactive as it adjusts to the weight of the new snow.In thinner snowpack areas (north and inland), deeper crust / surface hoar layers that were buried in December and early January may still be a concern. They are over 100 cm below the surface, but may be triggerable from thin spots.

Problems

Storm Slabs

An icon showing Storm Slabs
New snow is accumulating and storm snow from Tuesday may still be reactive. Natural and human triggered avalanches will be very likely in areas that receive more than 30 cm on Friday.
Sheltered slopes at lower elevations will offer the safest conditions.Watch for whumpfing, hollow sounds, shooting cracks or recent avalanches.Minimize exposure during periods of heavy loading from new snow and wind.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Very Likely

Expected Size

1 - 2

Persistent Slabs

An icon showing Persistent Slabs
A weak layer buried 60 cm below the surface has potential for human triggering. Storm slab avalanches may also step down to this layer.
Avoid shallow, or thick to thin snowpack areas where triggering a deeper layer is more likely.Minimize overhead exposure during periods of heavy loading from new snow and wind.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

1.5 - 2.5

Valid until: Feb 2nd, 2018 2:00PM

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