Avalanche Forecast

Issued: Jan 14th, 2017 4:17PM

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

ghelgeson, Avalanche Canada

Northwest Inland.

It's time to reign the terrain choices way in. Stick to simple terrain free of overhead hazard. The potential for large destructive avalanches is significant as snow, warm temps and strong wind continue to impact the region through the weekend.

Summary

Confidence

Moderate - Forecast snowfall amounts are uncertain

Weather Forecast

The NW Inland is expected to remain dark & stormy for the forecast period as high-energy systems continue to impact the NW Coast and spill into the mountains of the interior.SUNDAY: Freezing level around 1000m, 5 to 15cm of snow expected with the bulk of the snowfall occurring Sunday night, strong southwest wind. MONDAY: Freezing level around 1300m, 5 to 10cm of snow, strong to extreme southwest wind. TUESDAY: Freezing level around 1500m, moderate to strong southwest wind, no significant precipitation.

Avalanche Summary

Deep persistent slab avalanches continue to be reported in the Ningunsaw area, including natural and explosive triggered size 2.5 avalanches running on basal facets on southwest aspects. A natural size 2 wind slab avalanche was reported in the southern part of the region on Thursday, releasing on a wind-loaded northeast alpine slope.As the storm cycle continues, we can expect an increase in avalanche activity, including very touchy storm slabs that have the potential to trigger large deep persistent slab avalanches.

Snowpack Summary

5 to 30 cm of snow fell Friday night into Saturday accompanied by light to moderate southwest wind and warm temperatures. This new snow is expected to form a widespread storm slab problem that should be very touchy on lee features at all elevations. The new snow is burying a layer of feathery surface hoar crystals, which will likely allow for wide propagations in the storm snow. Snow depth at treeline varies from about 1 m in most areas to 2 m in deeper snowpack areas in the south and west of the region. The shallow snowpack areas mostly consist of weak faceted or sugary grains beneath hard slabs. With the additional load of new snow these hard slabs may produce surprisingly long fractures resulting in large avalanches, and in some instances they may step down to weak faceted snow crystals near the ground.

Problems

Deep Persistent Slabs

The potent mix of snow, wind and warm temperatures could be the straw that breaks the proverbial camel's back. As the storm continues to impact the region the likelihood of both natural and human triggered deep destructive avalanches is elevated.

Avoid all avalanche terrain during periods of heavy loading from new snow, wind, or rain.Be aware of the potential for full depth avalanches due to weak layers at the base of the snowpack.Stick to simple terrain and be aware of what is above you at all times.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

2 - 4

Storm Slabs

New snow, warming temperatures and strong winds have created a widespread storm slab problem. Storm slab avalanches in motion may step down resulting in large destructive avalanches.

Avoid all avalanche terrain during periods of heavy loading from new snow, wind, or rain.The new snow will require several days to settle and stabilize.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely - Very Likely

Expected Size

1 - 3

Valid until: Jan 15th, 2017 2:00PM