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Avalanche Forecast

Jan 3rd, 2019–Jan 4th, 2019
Alpine
4: High
The avalanche danger rating in the alpine will be high
Treeline
4: High
The avalanche danger rating at treeline will be high
Below Treeline
3: Considerable
The avalanche danger rating below treeline will be considerable
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
3: Considerable
The avalanche danger rating below treeline will be considerable
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.

Heavy snowfall and high wind are producing touchy storm slabs. Give the snowpack time to stabilize.

Confidence

Low - Intensity of incoming weather systems is uncertain

Weather Forecast

THURSDAY NIGHT: Snow, 20-30 cm. Moderate south wind with extreme gusts. Freezing level rising to 1800 m.FRIDAY: Heavy snow, 20-35 cm. Moderate to strong southwest wind with extreme gusts. Freezing level dropping to 1200 m.SATURDAY: Flurries, 8-15 cm snow. Light south wind gusting moderate. Freezing level 1100 m.SUNDAY: Flurries, 5-12 cm snow. Moderate southwest wind. Freezing level below 1000 m.

Avalanche Summary

On Thursday, storm slab avalanches to size 2 were failing with explosives and skier traffic. Through the day, rain falling to 1500 m triggered loose wet and wet slab avalanches. Prior to Wednesday, avalanche activity seems to have tapered off as temperatures cooled off over earlier in the week. On Sunday there were reports of a few explosives controlled size 1-1.5 storm and wind slabs. On Saturday reports indicated several explosives controlled size 2 storm and wind slabs in the alpine and treeline. Most of these avalanches were running on a layer of surface hoar buried around December 26.

Snowpack Summary

Heavy snowfall, rising freezing levels and extreme winds are setting up a widespread storm slab problem. Around 40-80 cm of new snow since Wednesday adds to 30-50 cm of snow from the past week. This new load potentially sits on a weak layer of feathery surface hoar at treeline elevations and on a crust below 1800 m.A weak layer of sugary facets and surface hoar lies around 150 to 200 cm deep in the snowpack. There have not been reports of avalanches on this layer for over a week. That being said, this layer may still exist in isolated areas around treeline in some parts of the region. The additional weight of the new snow could stress deeper weak layers too.

Avalanche Problems

Storm Slabs

Large natural avalanches are expected with heavy deposits of new snow falling with extreme wind.
Avoid all avalanche terrain during periods of heavy loading from new snow, wind, or rain.If triggered the storm slabs may step down to deeper layers resulting in very large avalanches.Minimize exposure to overhead avalanche terrain, large avalanches may reach run out zones.

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Very Likely

Expected Size: 1.5 - 3.5