This summary will expire on December 23rd, as another storm system approaches Arizona. Natural and human triggered avalanches will be unlikely for the next ~72 hours. There is little powder snow available for transport and new wind slab formation over the next 3 days is unlikely. However, if you do venture into avalanche terrain, watch for unstable snow in isolated areas and extreme terrain.
Watch for ice and hard snow on steep slopes - ice tools may be necessary to prevent dangerous sliding falls. Parties have reported that crampons and ice axes are a necessity for near/above treeline travel, and that overall, touring conditions are demanding.
Recent snowpits on December 17 and 18 show a decrease in failure propagation propensity for the near surface facets associated with recent rain crust (see previous summary), though this is still a weak layer interface to be monitored in the future.
No new slab avalanches have been reported since the late November cycle.
Tomorrow is the winter solstice, with the least daylight of the year. Cold temperatures will likely prevail, and the more predictable and stable conditions of spring are weeks to months away. Most avalanche accidents happen during the months of January and February, so it is best to keep your open season mindset in check before you ski any avalanche terrain.
On Dec. 19th, we observed evidence of small (R1D1) avalanche debris on Lockett Meadow Rd. These likely released during one of our December rain events.
Near and Above Treeline:Coverage is ~1.5 meters or more. A group reported difficult, icy travel and skiing conditions on December 18th. Currently the snowpack shows variable strength, poor structure, and low energy/propagation propensity.
Below Treeline:Coverage for ski touring on many slopes above 10,000 ft is still good for this time of year, but early season hazards such as downed trees, stumps, and boulders may still remain hidden near the surface at lower elevations. Conditions are variable and overall demanding, but generally better snow for ski touring has been found below treeline. Southerly and sunny slopes are thin or completely bare below 9,500 ft.
Submit your observations here. You may save a life! The link to this form is now on our home page and snowpack menu.
As of December 13th, uphill travel at the Arizona Snowbowl is OPEN. Also, the Kachina Peaks Wilderness is accessible by the Humphreys trail and the Kachina trail from the lower parking lots at Arizona Snowbowl.
For information on uphill travel within the Arizona Snowbowl ski area, please refer to www.flagstaffuphill.com and https://www.snowbowl.ski/the-mountain/uphill-access/ for details.
Weather updated Friday December 20
The past week was cold and windy. In the aftermath of a significant cold front brushing to our north, temperatures dipped into the single digits and below 0°F at some locations. Wind chills fell below 0°F on Monday night. Strong winds blew out of the NE from Monday night December 16 through Wednesday morning Dec 18 with a maximum gust of 73 mph, and average wind speeds of 40 mph.
The end of the week will bring warming with a passing high pressure ridge. The weekend should be nice with mild temperatures and mostly cloudy skies. Fair weather will be short-lived. Early next week unsettled weather returns to the region with a Pacific trough entering our region. Although most of the energy appears to be tracking south of northern Arizona, we may get modest snowfall. The greatest chances of accumulation will be Tuesday, Christmas Eve day. The snow line will be from 5500-7000 feet. High elevation temperatures will remain mostly below freezing throughout the upcoming week as the weather gradually settles.
Arizona Snowbowl Ski Patrol reports a 47" (119 cm) base at 10,800 feet. Snowslide SNOTEL reports a 32” (81 cm) snow depth. So far this winter we have had 92" (234 cm) of snowfall at 10,800 feet.
Since December 13th, SNOTEL temperatures have ranged between -4°F on December 17th and 45°F on December 13th. ASBTP station (11,555 ft) reported a low of 2°F on December 16th and a high of 41.6°F on December 13th.