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Avalanche Forecast

Jan 6th, 2019–Jan 7th, 2019
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
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: Sea To Sky.

As the stormy weather eases off and temperatures drop, the snowpack will begin to gain some strength. However, storm slabs are still likely to be encountered and could be reactive to human triggering, especially in wind loaded areas.

Confidence

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

Weather Forecast

SUNDAY NIGHT - Mainly cloudy with scattered flurries / southwest winds, 15-35 km/h / alpine low temperature near -10MONDAY - Cloudy with sunny periods / west winds, 20-25 km/h / alpine high temperature near -10TUESDAY - A mix of sun and cloud with isolated flurries / southeast winds, 15-20 km/h / alpine high temperature near -5 WEDNESDAY - Snow, up to 20 cm / southeast winds, 20-40 km/h / alpine high temperature near -2 / freezing level 1000 m

Avalanche Summary

On Sunday, numerous explosives triggered avalanches up to size 2 were reported in the region. Many of these were cornice failures.On Saturday, numerous natural avalanches to size 3 and explosives triggered avalanches to size 2.5, and one size 1 human triggered avalanche were reported in the region. On Friday, numerous explosives triggered avalanches to size 3 and one human triggered size 1.5 were reported. A group also reportedly remotely triggered a storm slab 20 m away with a 80-100 m crown.A widespread natural avalanche cycle up to size 3, and human triggered avalanches to size 2 were reported in the region on Thursday.

Snowpack Summary

The Sea to Sky region has received approximately 100-140 cm of recent storm snow with strong to extreme southerly winds. Cornices are growing and slab formation is likely widespread.At treeline and below, the storm snow sits on two weak layers that are down 80-100 cm and 150-200 cm. These layers consist of surface hoar (feathery crystals) in more sheltered areas and a crust on solar aspects and on all aspects below 1500m.In the lower snowpack, a weak layer of facets (sugary snow) is now over 200 cm deep. There have been no reports of avalanches on this layer for over a week, but it may still be reactive to heavy loads (such as a cornice fall) in isolated areas.

Avalanche Problems

Storm Slabs

Slabs are likely to be most reactive in wind loaded areas.
Whumpfing, shooting cracks and recent avalanches are all strong inicators of unstable snowpack.Be careful with wind loaded pockets, especially near ridge crests and roll-overs.Be alert to conditions that change with elevation.

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Possible

Expected Size: 1.5 - 2.5

Cornices

Recent new snow and strong to extreme wind southerly wind has promoted rapid cornice growth.
Give cornices a wide berth when travelling on or below ridges.Be aware of the potential for cornice failures to trigger slab avalanches.

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

Elevations: Alpine.

Likelihood: Possible

Expected Size: 1 - 2