Permafrost
The permafrost is a defining characteristic of the tundra biome. In the tundra summers, the top layer of soil thaws only a few inches down, providing a growing surface for the roots of vegetation. For a soil to be considered permafrost, it must be frozen for at least two consecutive years or longer.
This is a image of permafrost in
the Russian Tundra!
the Russian Tundra!