These three types of metamorphosis transform individual snowflakes into ice crystals and create spaces under the snow where small animals can move.
Subnivean fauna includes small mammals such as mice, voles, shrews, and lemmings that must rely on winter snow cover for survival.
The sinuous tunnels left by these small mammals can be seen from above when the snow melts to the final inch or so.
Some winter predators, such as foxes and large owls, can hear their prey through the snow and pounce from above.
Female polar bears also den in snow caves to give birth to their young.
Destructive metamorphosis begins as the snow makes its way to the ground, often melting, refreezing, and settling.
As time goes on, snow settles, compacting air spaces, a process expedited by the packing force of the wind.
This occurs because the surface area of the ice crystal decreases and it causes less refraction and scattering of light.
As more water comes down from the surface, it creates more heat and brings the entire snowpack column to near equal temperature.
Snow around trees and under canopies melts faster due to the reradiation of long-wave radiation.