Northern San Juan

No avalanches were observed.

You can almost feel the thermostat getting cranked up out there. After several colder days, today warmed quickly under bluebird skies and light winds gusting moderate out of the west and the north. Winds were not strong enough to cool snow surfaces, as things softened by 11am, but winds picked up and switched direction around midday.

The recent 90-mile-per-hour winds eroded away much of the soft snow that remained above treeline, which was made obvious by abundant raised old ski tracks and scoured slopes. The snowpack has generally been beaten down by the sun, the wind, and now the warm temperatures. In cold, shady areas, the snowpack remains cold and dry. But this incoming warm-up with temperatures above freezing for several days could finally begin to penetrate into the shady slopes and begin to melt the snowpack. I dug pits on north, northwest, west, and southwest-facing slopes at 11,600 feet. The snowpack couldn't have been more different on sunny versus shady slopes. On the west and southwest-facing slopes, meltwater had completely saturated the snowpack and a thick stout melt-freeze crust has formed. On northwest, the last warm weather caused meltwater percolate down and pool on the bottom of the February slab, forming an ice lense. But below that, the snowpack remains dry. And on north, the snowpack was completely cold and dry with our ugly old Persistent Slab structure and hard-propagating results. The structural recipe for Wet Slab avalanches seems to be most commonly found on east- and northeast-facing slopes, but northwest- and higher-elevation west-facing slopes could also come into play as water flushes to the ground and saturates the basal depth hoar.