(from the Icelandic). A sudden and often catastrophic outburst of water from a glacier during a volcanic eruption. The term is also used to describe when an ice-dammed lake bursts or an internal water pocket escapes, resulting in flooding.

The high discharge evident in this stream along the front of Thompson Glacier, Axel Heiberg Island, Canadian Arctic, is the result of the sudden release of water from ice-dammed Between Lake. Photo M. J. Hambrey, 1975.