Flagstaff, Arizona - Backcountry of The San Francisco Peaks and Kachina Peaks Wilderness
Format and Limitations Statement
With the recent storm events, the likelihood of natural and human triggered avalanches has increased significantly. On January 25th, while evaluating conditions, Arizona Snowbowl Ski Patrol triggered a small soft slab release
on a northwesterly slope near treeline. This occurred in an area that was closed to the public. Extensive wind slab fracturing from ski cutting was observed this morning above treeline. There is a reactive layer within the storm snow 60 cm above ground.
Prior to the past week of snow, there was not much of a backcountry snowpack and much of the snow was limited to upper mountain northerly slopes. That's really changed and within the past 7 days the Snowslide Canyon SNOTEL site snow depth went from 11" to 50+" in the past 48 hours. AZ Snowbowl reports 59” of new snow in this storm cycle.
There is very limited information available for backcountry slopes at this time. Backcountry travelers should carefully assess any slope steeper than 30°, as well as any slope connected to steeper (>30°) slopes above. Venture into this new snow with an "assessment" mindset
by selecting conservative terrain. Assess the bonding and reactivity of new storm and wind slabs.
Reactive wind and storm slabs are probable. Reactive persistent slabs (new snow resting on weak basal facets) are possible. Those venturing out onto the brand new snow should approach the unknown with prudence, particularly until we all get a chance to size up the snowpack’s structural and mechanical properties.
Most of the snowpack is powder snow to the ground. Expect rock and log strikes in rocky and forested terrain.
Expect rock and log strikes in rocky and forested terrain.
Westerly and southerly winds may have produced wind slabs near/above treeline on easterly and northerly slopes. Changes in wind direction may produce slabs on other aspects.
Look for convex pillows of wind-drifted snow on the lee side of ridges and other terrain features. The Wind Slab may have a chalky look and feel. Wind Slabs can be very hard, and may present a hollow drum like sound as you traverse across slope.
There is a bit of uncertainty, but it is possible that new snow has accumulated on early-season faceted snow, creating a persistent slab problem. If this is an issue, it will likely be limited to above/near treeline northerly aspects, particularly smoother cindered slopes with few anchors.