Permafrost
That's called the 'permafrost'.
Permafrost.
This is called permafrost, where soil, rock, or sediment remains below freezing temperatures for two or more consecutive years. It can be found in polar regions or high mountain ranges where the ground is permanently frozen.
Artic Tundra
what is a vast flat treeless region in which the subsoil is permanently frozen is called
permafrost
Permafrost
Permanently frozen soil anywhere is called permafrost.
tundra
Tundra is a flat, treeless plain where the subsoil is frozen
Taiga