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Avalanche Forecast

Jan 24th, 2016–Jan 25th, 2016
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
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
4: High
The avalanche danger rating in the alpine will be high
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.

It looks like one more dry day before the next round of warm storms hit the Coast this week.

Confidence

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

Weather Forecast

Monday: Cloudy with flurries. The freezing level rises to 1200-1400 m and winds are light or moderate from the S-SW. Tuesday: Periods of snow – 15-25 cm. The freezing level is around 1400-1600 m. Winds increase to moderate or strong from the SW. Wednesday: Moderate to heavy snow or rain. The freezing level spikes to around 2000 m and winds remain strong from the S-SW.

Avalanche Summary

No new natural avalanche activity was observed on Saturday. Explosives control produced mostly small (size 1) storm slabs with a couple deeper size 2 slabs from steep rocky slopes. Clear weather gave a better picture of the widespread natural cycle on Thursday and Friday. Most observers reported numerous size 2-3 slabs from all aspects and elevations. Many of these slabs released on the mid-January surface hoar, released on relatively low angle slopes, and showed very wide propagation.

Snowpack Summary

The "Pineapple Express Light" dumped 80-160 mm of precipitation on the South Coast this week. Most of this fell as snow above 1800-2000 m (over 1 m) with mixed rain and snow or just heavy rain below 1800 m. Heavy snow and strong winds have formed deep and dense wind slabs in exposed lee terrain and caused substantial cornice growth. Expect to find a rain crust at or near the surface (below 10-20 cm of fresh snow) at lower elevations. The early and mid-January surface hoar layers may have been wiped out by the storm and subsequent avalanche cycle. These layers would be down between 100 and 150 cm deep now. Tread cautiously until we know more about the state of these persistent weaknesses. The mid and lower snowpack is generally strong, with the exception of shallower snowpack areas that may be more faceted.

Avalanche Problems

Wind Slabs

Previously strong southerly winds created pockets of dense wind slab in exposed lee and cross-loaded terrain. 
Use ridges or ribs to avoid pockets of wind loaded snow.>Choose well supported terrain without convexities.>

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

Elevations: Alpine, Treeline.

Likelihood: Possible

Expected Size: 1 - 4

Cornices

Cornices are becoming large and may fail naturally or under the weight of a person or snowmobile. 
Give cornices a wide berth when travelling on or below ridges.>

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

Elevations: Alpine, Treeline.

Likelihood: Possible

Expected Size: 1 - 3

Persistent Slabs

Two layers of buried surface hoar could still be found down 100-150 cm deep. Triggering may still be possible with heavy loads in specific features (slopes near treeline that did not previously slide).
Whumpfing, shooting cracks and recent avalanches are all strong inicators of unstable snowpack.>Be aware of the potential for large, deep avalanches due to the presence of buried surface hoar.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Unlikely - Possible

Expected Size: 2 - 5