Avalanche Forecast

Issued: Jan 23rd, 2018 5:38PM

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

Avalanche Canada jsmith, Avalanche Canada

New snow and wind are creating deeper and increasingly destructive storm slabs ripe for human triggering. Sticking to simple terrain would be a great way to manage the elevated hazard on Wednesday.

Summary

Confidence

Moderate - Timing, track, or intensity of incoming weather system is uncertain

Weather Forecast

Tuesday Night: 15-25cm of new snow / Moderate to strong southwesterly ridgetop winds / Freezing level rising to around 1400m.Wednesday: 5-10 cm of new snow / Moderate southwesterly ridgetop winds / Freezing level around 1000m.Wednesday night: 20-30 cm of new snow / Strong southerly ridgetop winds / Freezing level around 800m.Thursday: 20-30 cm of new snow / Strong southerly ridgetop winds / Freezing level around 800m.Friday: 15-20cm of new snow / Light to moderate southwesterly ridgetop winds / Freezing level around 500m.

Avalanche Summary

On Tuesday, a size 1.5 skier triggered storm slab avalanche was reported near Mt. Seymour. With more snow and wind on the way, natural and human-triggered storm slab activity should continue throughout the week.

Snowpack Summary

In recent days the region was pummeled by heavy precipitation with the rain line hovering around 800m. As of Tuesday morning, the 72 hour precipitation totals were up to 130mm on the North Shore mountains with closer to 60mm falling north of the Fraser Valley. Strong to extreme winds have redistributed the new snow into deep, dense and potentially destructive storm slabs while rain has saturated the snowpack at lower elevations. The reactivity of the new storm slabs is likely to vary greatly depending on elevation/ temperature and orientation to wind. In general, I would expect the touchiest conditions to exist in exposed, higher elevation terrain.

Problems

Storm Slabs

An icon showing Storm Slabs
An impressive storm has just occurred, and deep and dense storm slabs lurk in lee and cross-loaded terrain. New snow and wind on Tuesday will add to this ongoing storm slab problem.
Be alert to conditions that change with elevation and time of day.The new snow will need time to settle and stabilize.Avoid all avalanche terrain during periods of heavy loading from new snow, wind, or rain.

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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