A layer of frozen ground which forms as part of the seasonally frozen ground (in areas free of permafrost or with a lowered permafrost table); remains frozen throughout one or several summers, and the
n thaws.
A layer of frozen ground which forms as part of the seasonally frozen ground (in areas free of permafrost or with a lowered permafrost table), remains frozen throughout one or several summers, and the
n thaws
Persisting for an indefinite time longer than one year. Perennial refers to the persistence of an object rather than, for example, to the duration of a measurement. See multi-Annual.
A solid that does not deform until it reaches a critical value of stress, after which it will yield infinitely. Some glaciologists say that ice is a perfectly plastic substance. That is, brittle and c
apable of cracking like a solid, yet deformable and capable of flowing at other stresses.