4.1.9 Day 2, 6AM: Radiative recrystallization
The intense vertical thermal gradient present the next morning (day two) has transported moisture from lower down in the snowpack to the top layer, causing the ice grains in about the top 5 cm (1.9 in) of the snowpack to grow. This process, known as radiative recrystallization, involves two phase changes: one from ice to water vapor in the lower snowpack, the other from water vapor back to ice in the upper snowpack.