Afternoon Backcountry Avalanche Forecast for Gunnison Issued 12/16/2008 4:15 PM by John Snook Weather Discussion Low pressure will continue to deepen over California during the next 36 hours. Southwest flow ahead of the trough keeps feeding moisture into the state. Mountain snowfall continues for aspects favored by southwest, especially the Southern San Juans, although accumulations will be less than the previous 24 hours. Gusty southwest winds will continue into Wednesday. A relative lull in snowfall activity is likely during Wednesday. Low pressure starts to eject toward Colorado Wednesday night and crosses the state on Thursday which will bring an increase in snowfall intensity again. Winds will gradually veer from south to west on Thursday which will change the focus for heavier snowfall from the Southwest Mountains to the Central Mountains. Friday brings a brief break from the unsettled weather. Very cold temperatures and more mountain snow are expected to return for the weekend. Low pressure will continue to deepen over California during the next 36 hours. Southwest flow ahead of the trough keeps feeding moisture into the state. Mountain snowfall continues for aspects favored by southwest, especially the Southern San Juans, although accumulations will be less than the previous 24 hours. Gusty southwest winds will continue into Wednesday. A relative lull in snowfall activity is likely during Wednesday. Low pressure starts to eject toward Colorado Wednesday night and crosses the state on Thursday which will bring an increase in snowfall intensity again. Winds will gradually veer from south to west on Thursday which will change the focus for heavier snowfall from the Southwest Mountains to the Central Mountains. Friday brings a brief break from the unsettled weather. Very cold temperatures and more mountain snow are expected to return for the weekend. Weather Forecast Fields Tuesday Night Wednesday Wednesday Night Temperature (°F) 5 to 10 18 to 23 12 to 17 Wind Speed (mph) 15 to 25 15 to 25 15 to 25 Wind Direction SW SW SW Sky Cover Overcast OV Overcast OV Overcast OV Snow (in) 2 to 4 2 to 4 4 to 6 Snowpack Discussion An avalanche warning remains in effect for the Gunnison zone. Snowfall since Monday afternoon has amounted to 10" around Crested Butte and close to a foot around Schofield Pass. This fell on top of weekend storm snow that varied from 6 inches to around 2 plus feet across the zone. The snowpack was already quite weak and a substantial new load has been added. Persistent southwest winds have strengthened during the day especially above treeline. This combination is creating a dangerous snowpack. Prior to the recent snow and wind, observers reported a number of natural and human triggered avalanches since the weekend storm. The latest on Monday was a large natural avalanche that ran on a buried surface hoar layer in the Anthracites. Backcountry visibility has been limited, so observations have been limited. The new snow load is resting on a weak base of faceted snow near the ground. Buried surface hoar has been noted and some observers are reporting a pinkish layer of desert dust within the recent storm snow. An avalanche warning remains in effect for the Gunnison zone. Snowfall since Monday afternoon has amounted to 10" around Crested Butte and close to a foot around Schofield Pass. This fell on top of weekend storm snow that varied from 6 inches to around 2 plus feet across the zone. The snowpack was already quite weak and a substantial new load has been added. Persistent southwest winds have strengthened during the day especially above treeline. This combination is creating a dangerous snowpack.

Prior to the recent snow and wind, observers reported a number of natural and human triggered avalanches since the weekend storm. The latest on Monday was a large natural avalanche that ran on a buried surface hoar layer in the Anthracites. Backcountry visibility has been limited, so observations have been limited. The new snow load is resting on a weak base of faceted snow near the ground. Buried surface hoar has been noted and some observers are reporting a pinkish layer of desert dust within the recent storm snow. Avalanche Danger The avalanche danger for the Gunnison zone is overall HIGH. Natural and human triggered avalanches are likely on any slope greater than about 30 degrees. Conditions in the backcountry are extremely tender. All slopes near and above 30 degrees should be avoided at this time. If you do not have the skills to evaluate the snowpack or terrain, it’s best to stay out of the backcountry until things settle down.