Avalanche Forecast

Issued: Jan 23rd, 2018 5:06PM

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

Avalanche Canada jsmith, Avalanche Canada

Expect hazard to be one step higher than forecast in localized areas that receive 30cm or more of new snow Tuesday night. Cautious route finding will be Critical to playing safe on Wednesday.

Summary

Confidence

Moderate - Forecast snowfall amounts are uncertain

Weather Forecast

Tuesday Night: 10-25cm of new snow / Moderate to strong southwesterly ridgetop winds / Freezing level around 1000m.Wednesday: 5-10 cm of new snow / Moderate southerly ridgetop winds / Freezing level around 1200m.Thursday: Mostly cloudy with flurries / Moderate southerly ridgetop winds / Freezing level dropping to around 800m.Friday: Mostly cloudy with isolated flurries / Light to moderate southwesterly ridgetop winds / Freezing level around 700m.

Avalanche Summary

On Monday, two explosive triggered size 3 storm slab avalanches were reported on north aspects between 2000-2300 m. in the Duffey Lake area. A natural size 3 storm slab avalanche also occurred in this area on Sunday. Looking forward, forecast snow and wind will promote ongoing storm slab avalanche activity, especially in higher elevation, lee terrain.

Snowpack Summary

By Tuesday morning the 72 hour snowfall totals were around 60cm in the Duffey/ Tenquille areas. Thanks to strong to extreme southwest winds, I would anticipate redistribution of the recent storm snow at all elevation bands with storm slabs lurking in lee and cross-loaded features. Further south in Coquihalla area, 72 hour storm totals were closer to 35 cm and winds were much lighter.50-120cm below the surface you'll likely find a few crusts that were buried during the first few weeks of January. Due to limited observations, not much is known about the current reactivity of these layers.The lower snowpack includes the mid-December crust layer. I'd expect an improving bond at this interface; however, the load of the new snow may tip the balance and reactivate this layer in isolated terrain - particularly in the north of the region where it's shown prolonged reactivity in snowpack tests.

Problems

Storm Slabs

An icon showing Storm Slabs
Forecast new snow and wind on Tuesday night will add to an ongoing storm slab problem with increased reactivity expected at treeline and above.
The new snow may require several days to settle and stabilize.Stay off recent wind loaded areas until the slope has had a chance to stabilize.Be cautious as you transition into wind affected terrain.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely - Very Likely

Expected Size

1.5 - 2.5

Valid until: Jan 24th, 2018 2:00PM

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