| Term: | Thufur |
| Definition: | Perennial hummocks formed in either the Active Layer in Permafrost areas, or in the seasonally frozen ground in non-permafrost areas, during freezing of the ground. The hummocks may be as much as 50 cm in height and 160 cm in diameter and can reform within 20 years following destruction. Growth is favoured by silty sediments and reasonably good drainage. |