Glacier variations in the Northern Patagonia Icefield between 1990/91 and 1993/94

Abstract

The snout variations of 18 outlet glaciers distributed in the Northern Patagonia Icefield between 1990/91 and 1993/1994 were elucidated by using oblique aerial photographs taken by hand-held 35 mm cameras. Although it was recognized that most glaciers showed retreats, the recession rates of most glaciers have generally declined when compared with the period from 1985/86 to 1990/91. For example, San Rafael Glacier had been retreating at a maximum rate of 300 m/a during the 1985/86-90/91 period, but between 1990/91 and 93/94, the left side (small part) of the snout has receded at a rate of only 20 m/a, while the right side (small part) has advanced at a rate of 17 m/a. On the other hand, Reicher Glacier showed the fastest recession rate of 1,183 m/a due to breaking up of the disintegrating snout in the proglacial lake. In general, the recession rates of the glaciers on the west side of the icefield were larger than those of the glaciers on the east side, a similar trend to the previous periods ; however, the differences were smaller than the previous periods.