Snow that has matured through multiple iterations of melt-freeze cycles, most often during the springtime.

Credit: Blackbird Guides

Corn snow is made up of a thick layer of large melt-freeze grains that support the weight of skiers and riders while frozen. Melt-freeze snow grains get larger as they mature and start to take on a shape similar to corn. As the surface of corn snow melts and softens, it makes for ideal conditions for edging skis, snowboards, or snowmobiles while also providing good snow stability. Good corn skiing or riding hinges on a decent overnight refreeze and timing your descent while only the top few inches have softened. As the depth of melting increases throughout the day, the chances for wet snow avalanches can quickly increase. 

The timing for ideal corn snow is as the top few inches of snow thaw to make edging easy, while the rest of the snowpack is frozen and supportive. Credit: Crested Butte Avalanche Center