Abyss Lake is a lake in southeastern Alaska. Lying on the eastern side of the Brady Glacier, it receives meltwater from it, which in turn flows into the Dundas River, Dundas Bay, Cross Sound and thence into the Pacific.A part of the Glacier Bay National Park and Preserve, its water is regularly blocked by an ice dam. When such a dam breaks in a glacial lake outburst flood, much of the lake's water is propelled into Dundas Bay, along with trees, ice chunks, and sediment.