Northern New Mexico

It's possible to trigger a persistent slab avalanche near and above treeline with the most likely slopes facing north through east.  Stiff slabs rest on top of weak facets and facet crust combinations in the upper 3 feet of the snowpack. Avoid steep slopes where you find obvious wind drifted pillows and stiffer snow underfoot. Winds have been shifting over the last several days and you may find stiff slabs in cross-loaded gullies and terrain features on other aspects. Pay attention to obvious signs of instability like shooting cracks and loud audible collapses and adjust your travels accordingly.  These types of avalanches can break wider than you think across terrain features producing a larger avalanche that could be big enough to injure or bury you. 

Today's advisory is sponsored by OnXBackcounrty Thank you for supporting the Taos Avalanche Center.

It'll be another warm and sunny day for us here in northern New Mexico as temperatures will climb into the 30's and low 40's.  With our high sun angle, this time of year, and intense sun at our southern latitude the upper portions of the snowpack on solar aspects have been becoming wet and moist by mid-morning.   Small wet loose avalanches are possible at lower elevations in steep terrain on slopes that are directly in the sun. SW winds will increase throughout the day and should help limit warming at upper elevations but will continue to stiffen snow surfaces at upper elevations.  

Prior to this recent round of snow, warm temperatures and periods of strong to moderate winds at upper elevations changed the overall snow surface.  South and west aspects have varying thicknesses of melt-freeze crusts.  Near and above treeline winds last week created stiff pencil hard supportable slabs (5 - 20cm) thick.  Beneath that is the 2 to 3 feet of snow that fell at the beginning of February, which has formed a thick slab capping the January facets that formed during the month-long high-pressure period.  This has led to several faceted crust layers in the upper portions of the snowpack with the January facet layer buried deeper below.

There are two faceted layers we were finding in the snowpack, with the first being just beneath wind or melt-freeze crusts and the other further down in the snowpack from the January high-pressure period. In snowpits, the most reactive layer was the upper faceted layer that was failing with easy to moderate force in stability tests just below the upper slabs or crusts.   Deeper down in the snowpack the January facet layer is showing signs of healing and rounding and has been compressed under the 3 feet of snow that fell at the beginning of February. We were not finding this layer to be reactive in tests and on most slopes is well insulated from the slabs above.  However, it may be possible to find this layer more reactive in shallower snowpacks. 

We are trending in the right direction with our current persistent slab problem as warm temperatures and time are helping ease the likelihood of triggering an avalanche. However, this trend should be short-lived as a significant storm is forecasted Tuesday into Thursday next week that could bring over a foot of snow and strong winds to our mountains. This will increase avalanche danger and could make these weak layers more reactive by the time the storm makes its exit.