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Avalanche Forecast

Mar 30th, 2018–Mar 31st, 2018
Alpine
3: Considerable
The avalanche danger rating in the alpine will be considerable
Treeline
3: Considerable
The avalanche danger rating at treeline will be considerable
Below Treeline
2: Moderate
The avalanche danger rating below treeline will be moderate
Alpine
3: Considerable
The avalanche danger rating in the alpine will be considerable
Treeline
2: Moderate
The avalanche danger rating at treeline will be moderate
Below Treeline
2: Moderate
The avalanche danger rating below treeline will be moderate
Alpine
3: Considerable
The avalanche danger rating in the alpine will be considerable
Treeline
3: Considerable
The avalanche danger rating at treeline will be considerable
Below Treeline
2: Moderate
The avalanche danger rating below treeline will be moderate

Regions: South Columbia.

Storm slab avalanches are likely this weekend. The combination of fresh snow and clear skies will make the snow extra reactive on south-facing slopes.

Confidence

High -

Weather Forecast

SATURDAY: Sunny with moderate west wind, freezing level up to 1200 m, and alpine high temperatures near -6 C.SUNDAY: Cloudy with flurries increasing throughout the day (10-20 cm of snow), moderate west wind, freezing level up to 1200 m, and alpine high temperatures near -6 C.MONDAY: Mostly cloudy with light wind, freezing level up to 1000 m, and alpine high temperatures near -8 C.

Avalanche Summary

On Thursday, several size 1 skier triggered storm slab avalanches were reported. They were 30-50 cm thick and occurred on north and east aspects above treeline. One of the slabs subsequently triggered a larger size 2 avalanches that ran on the late-March crust. Some natural size 2-3 storm slabs avalanches were also reported in alpine terrain and a cornice fall in the Selkirks triggered a size 2.5 avalanche on an unidentified 2 m deep weak layer. On Tuesday and Wednesday, widespread natural avalanche activity was reported on all aspects in the alpine with size 1.5-3 storm slabs. These were predominantly failing on the recently buried late-March interface with crown depths of 30-40 cm and up to 100 cm in some areas. Several skier and remotely (from a distance) triggered avalanches up to size 2 were also reported in alpine terrain.

Snowpack Summary

Another 15-30 cm of snow on Friday brings the weekly total to 40-80 cm, with amounts tapering with elevation.The storm snow sits on an interface buried in late-March that consist of crusts below 1900 m and on south aspects, and surface hoar on shaded aspects at higher elevations.Pockets of surface hoar (buried mid-March) have been reported on shaded aspects at higher elevations and may be found approximately 60-80 cm below the surface.Deeper persistent weak layers from January and December are still being reported by professional observers, but are generally considered dormant.

Avalanche Problems

Storm Slabs

Storm slabs are widespread and will remain reactive to human triggering this weekend. The snow will be extra touchy on south aspects where storm slabs sit above buried sun crusts. Wind-loaded slopes above treeline are also suspect.
Be careful with wind loaded slopes, especially near ridge crests and roll-overs.Minimize exposure to steep, sun exposed slopes when the solar radiation is strong.Cornices become weak with daytime heating.

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Likely

Expected Size: 1 - 2.5