| Permafrost zone | Study sites | 1962-1968 | 1999-2001 | 2006-2007 | |||
| Lake number | Lake area (ha) | Lake number | Lake area (ha) | Lake number | Lake area (ha) | ||
| Continuous | Site 1 | 296 | 3350 | 350 | 3612 | 371 | 3651 |
| Site 2 | 7 | 161 | 7 | 141 | 7 | 122 | |
| Site 3 | 34 | 59 | 30 | 47 | 29 | 39 | |
| Site 4 | 10 | 110 | 13 | 119 | 13 | 124 | |
| Total | 347 | 3680 | 400 | 3919 | 420 | 3936 | |
| Isolated | Site 5 | 2 | 7 | 1 | 5 | 1 | 1 |
| Site 6 | 108 | 409 | 73 | 371 | 64 | 367 | |
| Site 7 | 8 | 6 | 3 | 4 | 3 | 3 | |
| Total | 118 | 422 | 77 | 380 | 68 | 371 | |