Flagstaff, Arizona - Backcountry of The San Francisco Peaks and Kachina Peaks Wilderness
Format and Limitations Statement
On Saturday, February 22, a natural avalanche was reported in the Crossfire Chute of Abineau Canyon. This was reported as a SSNR3D2 on a N-NE aspect near 10,500 ft.
Natural avalanches are possible. Human triggered avalanches are likely. Venture into this new snow with an "assessment" mindset
by selecting conservative terrain in which to gather information. Assess the bonding and reactivity of new storm and wind slabs. Temperature changes in the storm may have created poor bonding between layers.
Expect your immediate problem layers/slabs to be at and above the new/old snow interface. There is potential for new snow avalanches to overload and step down into previously dormant weak-layers associated with December rain-crust/facet layers.
Prior to the Feb. 22nd storm, the snowpack in the Kachina Peaks has proved to be high in strength, poor in structure, and showed little propagation propensity. Surfaces were a mix of wind and sun crust in exposed areas while pockets of soft snow lingered in isolated, protected areas.
As of 6am, February 23, Snowbowl reports 15" of new snow at 10,800 ft and Snotel reports 9" of new snow at 9,700 ft. Rain to 10500 ft or higher occurred Feb. 22.
Ice axe and crampons are strongly recommended as surface conditions can be very firm depending on the time of day, temperature and coverage. Always be cautious of wind slab formation on steep, leeward slopes. Observe for local signs of wind stripping and subsequent loading on leeward aspects wherever you travel above treeline. Where wind has not scoured snow, depths remain at 1-2 meters. New snow falling on these firm surfaces may be reactive, potentially sluffing with little provocation. Approach steep terrain with caution.
With a decrease in elevation comes a decrease in snow depth. Obstacles become the main hazard below 9500 feet, but are present on all aspects at all elevations. Sunny and southerly slopes below 9500 feet are getting difficult to navigate with skis. Always expect the unexpected. As new snow falls, obstacles may become covered and hidden just below the surface. Ski and snowboard with care after new snow.
Watch out for "bulls eye" data; collapses or shooting cracks that indicate instability in the snowpack and heed their warning by staying in simple terrain. Remember that this new snow fell on bare ground in wind scoured areas, or slick wind hardened snow surfaces which may prove to be an excellent bed surface.
Moderate southwest winds (with strong gusts) accompanied this storm. Winds are forecast to become northwest. Drifting snow was observed above 10,500 on Saturday afternoon, February 22. Approach ridges and leeward terrain with caution. Wind can deposit snow 10 times more rapidly than snow falling from the sky multiplying the load on the snowpack. Be suspicious of any steep slope with recent deposits of wind drifted snow.