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Avalanche Forecast

Feb 21st, 2013–Feb 22nd, 2013
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
3: Considerable
The avalanche danger rating below treeline will be considerable
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
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: South Rockies.

New snow and strong winds will rapidly raise avalanche danger with the onset of a winter storm on Friday.

Confidence

Poor - Timing, track, or intensity of incoming weather is uncertain

Weather Forecast

Synopsis: An intense storm will impact the region on Friday afternoon/evening, then briefly clearing on Saturday before another storm hits later on Sunday.Friday: 10-15 cm new snow is expected, starting in the afternoon. Strong southwesterly winds becoming gusty northwesterly to 90 km/h at ridgetop. Freezing level 1600 m.Saturday: Light snow in the morning, dry in the afternoon. Winds becoming light northwesterly. Freezing level 1000 m.

Avalanche Summary

Small soft slab avalanche could be skier-triggered on Thursday. Loose snow avalanches have also been reported in the recent new snow.

Snowpack Summary

Southeastern parts of the region have seen 30-60cm new snow in the last few days, while western areas have seen more like 10-20 cm. Mostly this snow has been light and overlies old wind slabs on higher north and east facing terrain and sun crusts on solar aspects. There may be localized areas where the wind has blown the new snow into isolated wind slabs in exposed areas. A surface hoar/facet/sun crust layer from mid February (12th) may be buried in the top 35 cm or so, but has not been widely reported from this region. Mid and lower snowpack layers are generally well settled and stable.

Avalanche Problems

Storm Slabs

Loading from new snow and wind will rapidly increase avalanche danger, particularly in exposed lee areas, where significant wind slab deposits are expected to develop.
Avoid all avalanche terrain during periods of heavy loading from new snow, wind, or rain.>Whumpfing, shooting cracks and recent avalanches are all strong indicators of an unstable snowpack.>Stick to simple terrain and be aware of what is above you at all times.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Very Likely

Expected Size: 2 - 5