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Avalanche Forecast

Dec 31st, 2017–Jan 1st, 2018
Alpine
2: Moderate
The avalanche danger rating in the alpine will be moderate
Treeline
2: Moderate
The avalanche danger rating at treeline will be moderate
Below Treeline
1: Low
The avalanche danger rating below treeline will be low
Alpine
2: Moderate
The avalanche danger rating in the alpine will be moderate
Treeline
2: Moderate
The avalanche danger rating at treeline will be moderate
Below Treeline
1: Low
The avalanche danger rating below treeline will be low
Alpine
2: Moderate
The avalanche danger rating in the alpine will be moderate
Treeline
1: Low
The avalanche danger rating at treeline will be low
Below Treeline
1: Low
The avalanche danger rating below treeline will be low

Regions: South Coast Inland.

Human triggered slab avalanches may become more likely as warm temperatures allow the storm snow to settle into a more cohesive slab. Keep a close eye on steep sun exposed slopes throughout the day too, warming may initiate natural loose avalanches.

Confidence

Moderate -

Weather Forecast

A warm dry pattern is expected for the next few days. The upper ridge will shift eastward on New Year's Day, which opens the door to warm air drifting in from the eastern pacific. This pattern is expected to stick with us for the foreseeable future. MONDAY: Temperature Inversion with below freezing air in the valley, above freezing (warmer) air between 1700 m and about 2500 m. Scattered cloud, light variable wind, no snow expected.TUESDAY: Temperature Inversion with below freezing air in the valley, above freezing (warmer) air between 1500 m and about 2800 m. Scattered cloud, light southwest wind, no snow expected.WEDNESAY: Temperature Inversion with below freezing air in the valley, above freezing (warmer) air between 1500 m and about 2800 m. Clear skies at dawn, a few clouds in the afternoon, light southwest wind, no snow expected.

Avalanche Summary

On Saturday a widespread avalanche cycle to size 1.5 was reported with avalanches failing within the recent storm snow.  A natural avalanche cycle likely occurred Friday night during the storm and may have continued into early Saturday morning.

Snowpack Summary

Friday night's storm produced about 30 cm in the north of the region and almost 40 cm in the south. That brings the total from the two successive storms to approximately 50 to 80 cm. The bulk of the wind during the storms was out of the southwest, south and southeast but there were periods of northeast and easterly winds too. All of this new snow rests on a variety of old surfaces including crust on solar aspects, old wind slabs, facets and isolated surface hoar below treeline. Wind slabs are common in wind exposed terrain, but it's thought the snow is largely unconsolidated in protected areas. As temperatures begin to warm on Monday the storm snow will likely settle into a more cohesive slab. A widespread melt-freeze crust buried mid-December exits throughout the region. This crust is down around 30 to 60 cm in the Duffey. Around the Coquihalla it's about 100 cm below the surface. This layer has not produced much in the way of avalanche activity, but it could come to life as the overlying slab gains cohesion.Beneath the mid-December crust, the lower snowpack is generally strong and well settled.

Avalanche Problems

Storm Slabs

50 to 80 cm of new snow has fallen in the last few days accompanied by wind mainly out of the south. Human triggered avalanches may become more likely as time, warm temperatures and wind loading allow the snow to settle into a more cohesive slab.
As the storm slab problem gets trickier, the easy answer is to choose more conservative terrain.Caution with open slopes and convex rolls at and below treeline, buried surface hoar may be present.Avoid wind loaded terrain at and above treeline, especially near ridge crests and roll-overs.

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Possible

Expected Size: 1 - 2

Loose Wet

Loose moist avalanches may run naturally on steep sun exposed slopes as previously cold snow is introduced to warm temperatures for the first time on Monday.
Avoid sun exposed slopes especially if the snow is moist or wet.Minimize exposure to solar aspects overhead, loose avalanches could travel surprisingly far.Stay in tune with the physical environment, conditions may change throughout the day.

Aspects: North, North East, East.

Elevations: Alpine.

Likelihood: Possible

Expected Size: 1 - 2