- A thick subsurface layer of soil that remains below freezing point throughout the year, occurring chiefly in polar regions: hilly terrain underlain by permafrostMore example sentences
- The permafrost below the topsoil is frozen all year around, and this prevents roots from penetrating deeply into the ground.
- In regions influenced by permafrost, water migrates along the thermal gradient from warm to cold, thereby feeding ice in the frozen core.
- In many high mountains regions, permafrost may be present.
More definitions of permafrostDefinition of permafrost in:
- The US English dictionary