RETREAT OF NELLIE JUAN GLACIER

Trees growing on the terminal moraine on the west side of Derickson Bay show that Nellie Juan Glacier was beginning to retreat by 1893. Ice recession was initially slow and photographs from the 1930s show the terminus back-wasting and down-wasting due to surface melting. However, by 1950 iceberg-calving was occurring across the full width of the terminus and this caused rapid retreat over the ensuing decades. By the 1990s the entire terminal bulb had disappeared and the terminus of Nellie Juan Glacier was confined in the narrow fjord at the south-western edge of Nellie Juan lagoon. Total retreat by 1992 amounted to 3.3 kilometers.

Ice margin positions during the 20th century retreat of Nellie Juan Glacier. Drawn from land-based and aerial photographs taken by William Field and Austin Post. The initial slow retreat occurred because the terminus was grounded at or close to sea level. However, iceberg-calving became much more important once the ice margin had retreated into deeper water of the lagoon and caused the rapid retreat since 1950.

Aerial photograph of Nellie Juan Glacier taken in 1986 by Austin Post.

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