The lakes of Juneau Icefield

This article is based on the followed accepted and published article about Juneau Icefield: Davies et al., 20221, which has been published in final form at: All data produced in this work, including shapefiles and an A0 poster of the icefield, are available as supplementary data with the final published version.

This article is part of a series on our work on Juneau Ice

Article authors: Bethan Davies, Jacob Bendle, Jonathan Carrivick, Robert McNabb, Christopher McNeil, Mauri Pelto, Seth Campbell, Tom Holt, Jeremy Ely, Bradley Markle

Glacial lakes of Juneau Icefield

We mapped 420 lakes, including 18 supraglacial, 28 ice-dammed, 47 proglacial ice-contact, 38 tarns in cirque basins, and 289 ice-distal lakes. This includes five moraine-dammed lakes. 12 of the outlet glaciers terminate in proglacial lakes. In total, the ice-contact proglacial lakes of Juneau Icefield cover 58.4 km2 with most of the water volume associated with outlet glaciers. Some of the larger proglacial lakes contain many icebergs.

lakes of Juneau icefield
Different kinds of lakes of Juneau Icefield. A, B, C: ice dammed lakes. D: Proglacial lake. E: Moraine-dammed ice-distal lake in a tarn. Figure produced by Bethan Davies.

Proglacial lakes were mapped in front of 47 glaciers, with large proglacial lakes in front of 12 outlet glaciers. As these outlet glaciers in the flat valley bottoms thin, they increasingly reach flotation, which can exacerbate calving, thinning and stretching of the glacier snout, and increased melt at the glacier terminus.

Cessation of calving

We mapped no icebergs at Mendenhall Glacier, suggesting that calving here is much reduced compared with 2004 14,15, as the glacier has receded into the shallow water at the end of the lake. Some of the terminus is in fact now on land.

mendenhall terminus
Mendenhall Terminus, 2022. Most of the glacier snout has now retreated out of the lake, with only a small calving margin and a few very minor icebergs. Credit: Bethan Davies

Instead, we note substantial calving at other glaciers (Tulsequah, Meade, Gilkey, Field), which may now be prone to this process. These glaciers, along with the Twin glaciers, have largely receded from their lakes.

West Twin Glacier has receded out of Twin Glacier Lake, meaning that frontal ablation is no longer a significant part of its mass balance.

Taku Glacier

The new moats mapped in front of Taku Glacier are likely to grow as the ice thins here and recedes into the substantial over-deepening upstream. This may re-initiate calving at this glacier16, and accelerate recession.

Taku Glacier, JUneau Icefield
Taku Glacier, Juneau Icefield. Map produced by Bethan Davies.
Taku Glacier
Taku Terminus, observed in 2022. Credit: Bethan Davies

Further reading

Introducing Juneau Icefield

The glaciers of Juneau Icefield

The lakes of Juneau Icefield

Structural glaciology of Juneau Icefield

Glacier disconnections of Juneau Icefield

Accelerating glacier mass loss in Juneau Icefield

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