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Avalanche Forecast

Feb 8th, 2016–Feb 9th, 2016
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
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
2: Moderate
The avalanche danger rating below treeline will be moderate
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: Sea To Sky.

Continued warming and solar radiation will drive the Avalanche Danger on Tuesday. Avalanches will become more frequent and destructive throughout the day.

Confidence

High

Weather Forecast

On Tuesday expect mainly clear skies, and freezing levels at about 3500m. On Wednesday the region should see increased cloud and freezing levels dropping to about 2200m. Moist snowfall (5-10cm) is forecast for Wednesday night and Thursday. Ridgetop winds should remain mainly moderate from the southwest for the forecast period.

Avalanche Summary

On Monday, warming and solar radiation triggered widespread loose wet avalanche activity in steeper, sun-exposed terrain. Large cornice collapses were also observed. Of note, warming also triggered a size 3.5 avalanche on the south face of Mt Currie. Similar action is expected on Tuesday. Warming will also increase the likelihood of triggering wet slabs and deep and destructive persistent slabs.

Snowpack Summary

Rising freezing levels and solar radiation will leave most surfaces moist or wet on Tuesday. This warming will also continue to have a significant destabilizing effect on the snowpack. On Friday between 60 and 100cm of new snow fell. Strong to extreme southwest winds shifted these accumulations into deep and dense storm slabs. Cornices were already large before the storm, and new growth is expected to be fragile. About 70-100cm below the surface, you likely find a rain crust which formed on January 28th. This crust is widespread and exists up to about 2050m. Where it still exists, the mid-January surface hoar layer may be found between 130 and 200 cm below the surface. The combination of ongoing heavy storm loading and warm temperatures has flushed out this weak layer in most areas. That said, warming and solar radiation forecast for the next few days may be what it takes to wake up this deep and destructive persistent weak layer.

Avalanche Problems

Loose Wet

Rising freezing levels and solar radiation on Tuesday will spark ongoing loose wet avalanche activity on sun-exposed slopes. Loose wet avalanches may also step down to deeper, more destructive layers.
Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet.>Be cautious of wet sluffing in steep terrain.>Be alert to conditions that change with aspect, elevation and time of day.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Very Likely

Expected Size: 1 - 4

Cornices

Cornices are huge and will become weakened by forecast warming and solar radiation. They can be destructive by themselves, and may also become the trigger for a large slab avalanche on the slope below. Use extra caution around ridge crests.
Extra caution needed around cornices with current conditions.>Pay attention to overhead hazards like cornices.>

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

Elevations: Alpine, Treeline.

Likelihood: Possible - Likely

Expected Size: 1 - 4

Storm Slabs

Although recently formed storm slabs have gained significant strength, they may remain sensitive to rider triggering in high elevation lee terrain.
Stay off recent wind loaded areas until the slope has had a chance to stabilize.>Be cautious as you transition into high elevation wind affected terrain.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Possible

Expected Size: 1 - 3