Avy Forecast 2.12.KX
Backcountry Avalanche Forecast for Front Range
Issued 02/12/2010 6:03 AM by John Snook
Highlights
The second Colorado avalanche related fatality occurred Thursday on a north aspect in the Sneffels range south of Ridgway. We will post more details as they become available.
Several inches of new snow on the west side of the Divide. Northwest flow will generate some periods of light snow through the weekend favoring northwest facing mountain ranges. Recent avalanche activity reported from steep wind loaded slopes and these areas remain most suspect. Wind loading will be greatest on north through southeast facing aspects where human triggered slides are probable.
Avalanche Danger
The avalanche danger for the Front Range zone is CONSIDERABLE on N-NE-E-SE aspects above treeline and N-NE-E aspects near treeline. Elsewhere, the danger is MODERATE.
Snow & Avalanche Discussion
Portions of the Front Range zone received light snow overnight. The west side of the Divide was favored with up to 4" of new snow. Persistent northwest flow will keep a chance for periods of light snow right on through the weekend. Daily accumulations are not likely to be very great, but with time, it could add up to several inches on favored northwest facing mountain ranges. The Front Range snowpack continues to exhibit various signs of instability. Earlier in the week, an observer reported several natural slides west of Cameron Pass. These all ran on northeast to east aspects above treeline. North facing slopes in the trees were sometimes completely faceted. An observer west of Nederland found one natural slide that ran Wednesday afternoon on a steep, wind-loaded, above treeline east slope. CDOT triggered a small soft slab Tuesday morning on the west side of Berthoud Pass running on a northeast aspect at 11,040 feet. A backcountry observer near Berthoud Pass found multiple collapses and stuck to low angle terrain.
Much of the Front Range zone snowpack is heavily wind-effected resulting in widely varying conditions. Above treeline, slopes with west through south aspects have very little snow while north through east aspects are heavily loaded. Persistent west to northwest winds will keep the avalanche danger higher on the easterly side of the compass. Forecast snowfall amounts are not likely to overwhelm the buried weak layers in the mid and lower snowpack, but fresh wind loading might. Winds have been stronger along and east of the Divide, so slab development will vary by aspect, elevation and location around the Front Range zone. Areas along and east of the Divide will be more reactive than well west of the Divide. Manage your terrain carefully and avoid steep slopes in wind-loaded areas where you find signs of instability such as cracking and collapsing.