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Avalanche Forecast

Nov 26th, 2018–Nov 27th, 2018
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
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
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

Regions: South Columbia.

Avalanche hazard will increase through the storm. If snowfall amounts exceed 25 cm, avalanche hazard will be higher than indicated.

Confidence

Low - Forecast snowfall amounts are uncertain

Weather Forecast

Snow forecasts identify the largest snowfall amounts occurring in the north and east of the South Columbia forecast region.MONDAY NIGHT: Flurries / Accumulation: 5-15 cm / Alpine temperature: High 0C / Moderate southwest ridge wind / Freezing level 1600mTUESDAY: Periods of snow / Accumulation: 5-20 cm / Alpine temperature: High -1C / Moderate southwest ridge wind / Freezing level 1500mWEDNESDAY: Cloudy with flurries / Accumulation: up to 10 cm / Alpine temperature: High -2C / Light to moderate southwest ridge wind / Freezing level 1400mTHURSDAY: Mainly cloudy with isolated flurries / Accumulation up to 5 cm / Alpine temperature: High -4C / Light southwest wind / Freezing level 1200m

Avalanche Summary

On Saturday, a large human triggered avalanche was reported on Meadow Mountain. The size 3 avalanche occurred on a steep, north aspect in the alpine and failed to ground, likely on a crust buried in October. Find the MIN report here.Earlier in the month, a natural avalanche cycle took place over the late October crust/facet combination. Be aware of the continued possibility for smaller avalanches to 'step down' or even initiate at this deeper layer. It exists primarily in the alpine.

Snowpack Summary

Snowfall through Monday afternoon has deposited 5-15 cm new snow around the region. Two layers, both consisting of a crust and weak surface hoar, are now buried down 30-40 cm and 45-60 cm respectively. Near the ground, sugary, faceted snow and crust buried late October supports the snowpack. The total snowpack depth varies from 110-160 cm in the alpine, with snowpack depth decreasing quickly with decreasing elevation.

Avalanche Problems

Storm Slabs

5-15 cm snowfall through the day on Monday has increased the load on this layer now buried about 30-40 cm deep. Slabs may be more reactive in wind-exposed terrain and areas where recent snow has a weak bond with this layer.
Watch for whumpfing, hollow sounds, shooting cracks or recent avalanches.Caution in lee and cross-loaded terrain near ridge crests.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Unlikely - Possible

Expected Size: 1 - 2.5

Persistent Slabs

A buried crust and faceted snow exists at the base of the snowpack in the alpine. This weak layer has already produced large avalanches in alpine terrain and ridge top features.
Be aware of thin areas that may propogate to deeper instabilites.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Unlikely - Possible

Expected Size: 1 - 3