Avalanche Forecast

Issued: Feb 6th, 2016 8:56AM

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

Avalanche Canada jlammers, Avalanche Canada

In the far western side of the region more snow is expected to fall. In these areas, the Avalanche Danger may be HIGH on Sunday.

Summary

Confidence

Moderate - Due to the number of field observations

Weather Forecast

On Sunday and Monday another windy storm will impact the region. Expect between 5-15mm of precipitation per 24 hour period with freezing levels climbing from 500m on Sunday morning to 1800m by Monday afternoon. On Tuesday, expect a mix of sun and cloud with the freezing level shooting up to 2500m. Ridgetop winds should remain strong to extreme from the southwest for the forecast period.

Avalanche Summary

In recent days wind and snow promoted natural slab avalanche activity to size 2 in the Howson Range. Continued snow and wind on Sunday will promote ongoing wind slab activity with the potential to step down to deeper, more destructive persistent weak layers.

Snowpack Summary

New snow and wind forecast for Sunday will create reactive new wind slabs throughout the day adding to an ongoing wind slab problem. New snow accumulations will also add mass and reactivity to a developing slab which overlies recently buried surface hoar. This layer was observed in the Hankin area and may exist in many other places. The early or mid January surface hoar layer is generally 30-50 cm deep, although it may be buried by up to 100cm of snow in the far west of the region. Observers have found this persistent weakness on all aspects and at all elevations. It consistently produces moderate "pops" results in snowpack tests. Below this, the Boxing Day surface hoar problem may also be lurking. The mid and lower snowpack is generally quite weak and faceted, especially in lower snowpack areas such as the Babines.

Problems

Wind Slabs

An icon showing Wind Slabs
Moderate amounts of new snow and extreme winds will promote ongoing wind slab activity at treeline and in the alpine. Hard wind slabs may propagate over surprisingly wide distances.
Stay off recent wind loaded areas until the slope has had a chance to stabilize.>Be aware of the potential for wide propagations due to the presence of hard windslabs.>

Aspects: North, North East, East, South East, South, South West.

Elevations: Alpine, Treeline.

Likelihood

Likely - Very Likely

Expected Size

1 - 3

Persistent Slabs

An icon showing Persistent Slabs
New snow has been slowly accumulating over a layer of facets and surface hoar, and in many places the overlying slab may now be primed for human triggering.
Be aware of the potential for large, widely propagating avalanches due to the presence of buried surface hoar.>Whumpfing, shooting cracks and recent avalanches are all strong inicators of unstable snowpack.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

1 - 4

Valid until: Feb 7th, 2016 2:00PM

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