Changes in Permafrost Distribution in Northeastern British Columbia

Abstract

Systematic observations of the distribution and thickness of the permafrost were made in northeastern British Columbia, Canada, along a traverse extending northeastward from Fort Nelson (58 49 N, 122 41 W) situated at an elevation of about 1000 ft (305 m) above sea level, across the southwest-facing Etsho Escarpment which rises to an elevation exceeding 2200 ft (671 m), and to the boundary of the Northwest Territories at an elevation of about 1500 ft (457 m) .... The traverse was underlain mostly by cretaceous shales, with sandstone forming the higher land. ... The thickness of the active layer was measured by probing with thin steel rods. ... Wherever possible, seismic lines were used for this measurement, since probing is then more likely to indicate the approximate base of the permafrost in the area. ... Probing below permafrost bodies from seismic lines and natural depressions in the landscape revealed, however, no inconsistent results within the study area.