In general, slab avalanches are unlikely on the San Francisco Peaks over Valentine's/President's day weekend. Loose wet avalanches will be possible during the warmer hours this weekend. There exists the remote possibility of finding some recently formed and reactive wind slabs in isolated terrain. With only minor amounts of snow available for transport, wind slabs may be small and likely confined to steep and extreme terrain near/above treeline and near ridgetops. Keep in mind that even small avalanches can have grave consequences in extreme terrain.
The last two storms have tracked just north or south of us, keeping things windy, but resulting in very little precipitation. The next chance of precipitation and wind is forecasted for Sunday/Monday, although moisture associated with the trough will likely remain north of Flagstaff. Any precipitation and additional winds this storm delivers will likely increase avalanche hazard. Until then, spring skiing and riding conditions are likely to persist on the San Francisco peaks, particularly on south facing slopes.
Overall, the snowpack has a complex and poor structure, moderate to good strength, and low reactivity. No new slab avalanches have been reported since the Christmas storm cycle.
Near and Above Treeline:Ice axe and crampons are strongly recommended as surface conditions can be very firm depending on the time of day and temperature. 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.
Below Treeline:With a decrease in elevation comes a decrease in snow depth. Obstacles become the main hazard below 9500 ft but are present on all aspects at all elevations. Sunny and southerly slopes below 9500 ft are getting difficult to navigate with skis. Always expect the unexpected. If any new snow falls next week then obstacles may become covered and hidden just below the surface. Ski and snowboard with care after new snow.
When daytime temperatures warm, stability on sunny aspects may deteriorate. Time your corn snow harvest appropriately. One relatively small wet slough was reported on Saturday, Feb. 1st, on a sunny southeasterly slope.
For springtime corn turns, timing is key to avoid hazards associated with a warming snowpack. With weekend temperatures >40°F forecast at 10,000 ft, avoid steep, sun exposed terrain as stability deteriorates during the heat of the day.
With only minor amounts of snow available for transport, wind slabs will be small and likely confined to steep and extreme terrain near/above treeline and near ridgetops. Keep in mind that even small avalanches can have grave consequences in extreme terrain.
Wind Slabs can be very hard, and may present a hollow drum like sound as you traverse across slope. Hard slabs are most prone to human triggering where they are thin/weak, and therefore, more susceptible to failure under a person's weight.
Always carry the 10 essentials and avalanche rescue gear for wintertime wilderness travel. Practice with your avalanche rescue gear. There is still space available in our avalanche courses.
Submit your observations here. You may save a life! The link to this form is now on our home page and snowpack menu.
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.
Updated Friday February 14
Unsettled weather early last week sent the brunt of precipitation to eastern Arizona and New Mexico. Locally a net accumulation of only two inches of new snow was reported at 10,800 feet. Strong storm and post-storm rap-around winds blew out of the east and northeast Tuesday, moving what little new snow had fallen onto leeward aspects. Cool crisp days and a gradual warming trend followed later in the week. Winds subsided and warm weather prevailed leading into the weekend. Breezes will kick up as a dry short wave passes on Friday and Saturday.
The next chance of significant precipitation is currently uncertain. A short wave trough out of the northwest, previously predicted to arrive on President’s Day, now appears to be shifting to our north, bringing only cooler temperatures and more breezy conditions. Normal to slightly below normal temperatures will linger into the workweek.
Arizona Snowbowl reported a 54" (137 cm) base at 10,800 feet. Snowslide SNOTEL reports a 45" (114 cm) snow depth. So far this winter, we have had 147" (373 cm) of snowfall at 10,800 feet.
Since February 7th, SNOTEL temperatures have ranged between 47° F on February 7th and 11° F on February 11th. ASBTP station (11,555 ft) reported a low of 7° F on February 11th and a high of 38° F on February 7th.