Tundra - Geographical Features
Permafrost
The ground underneath the tundra is frozen all year round. This is called Permafrost.
- Exploratorium: Tundra and Permafrost [http://icestories.exploratorium.edu/dispatches/big-ideas/tundra-and-permafrost/]
- National Snow and Ice Data Centre [http://nsidc.org/frozenground/ecology.html]