Avalanche Forecast

Issued: Feb 25th, 2017 6:40PM

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

Avalanche Canada ghelgeson, Avalanche Canada

Updated @ 09:30 Sunday: Significant overnight snowfall will make excellent fodder for wind and storm slabs. Evaluate each slope carefully and stay out of the wind today.

Summary

Confidence

Low -

Weather Forecast

SUNDAY: Flurries overnight Saturday through Sunday, accumulation 10-20cm possible/ Alpine temperature -7 C / Light east windMONDAY: Isolated flurries, accumulation 5-10cm possible Sunday night into Monday morning / Light to moderate west wind / Alpine temperature -8TUESDAY: Mix of sun and cloud / Light to Moderate west wind / Alpine temperature -9More details can be found on the Mountain Weather Forecast.

Avalanche Summary

Explosives control near Fernie resulted in a deep persistent avalanche on Friday; this avalanche was size 2.5 on a north aspect at 2000 metres, and is believed to have released on the mid-December facets. There was a report on Tuesday of a natural avalanche size 3.5 on Mt Hosmer on an East aspect at 2100 metres that appears to have released on or stepped down to the weak deep persistent layer of sugary facets near the ground. On Wednesday we had a report of a size 3.0 avalanche on "Big Steep Mother" bowl on a northeast aspect at 2100 metres in the alpine in the Lizard range. This avalanche appears to have been started by a cornice fall that released a storm slab that then "stepped down" to deeply buried weak facets.

Snowpack Summary

20 to 40 cm of storm snow from Saturday night now rests upon the 50 to 60 cm of storm snow from last week. This 70 to 100 cm is likely settling into a storm slab in sheltered locations, and is almost certainly forming a wind slab in wind affected terrain. This slab sits above a thick rain crust below 1900 m and a generally well settled snowpack. Isolated basal weaknesses may still exist in shallow snowpack areas. These weak areas appear to be on north-northeast aspects in the alpine. If the winds shift direction over the next few days, watch for new wind loading on south-west aspects.

Problems

Storm Slabs

An icon showing Storm Slabs
Deep storm slabs (70-100cm) will take some time to settle and bond to the old surface. This problem may linger in areas with a hard rain crust below the storm snow.
Be cautious as you transition into wind affected terrain.Use caution in lee areas. New snowfall mixed with wind loading will create slabs.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

2 - 3

Deep Persistent Slabs

An icon showing Deep Persistent Slabs
There have been two natural deep persistent slab releases in the past few days in the Lizard range. Both of these avalanches were on northeast aspects in the alpine, and released to size 3.0 or larger.
Be aware of the potential for large, deep avalanches.If triggered the storm slabs may step down to deeper layers resulting in large avalanches.

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

Elevations: Alpine, Treeline.

Likelihood

Unlikely

Expected Size

2 - 4

Valid until: Feb 26th, 2017 2:00PM

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