Bryan and Cherry Alexander / Square seracs (columns of ice) on a glacier by the Whittle Peninsula, Antarctica, 2009.

Bryan and Cherry Alexander / Seracs (columns of ice) on a glacier on the East coast of Drygalski Fjord, South Georgia, 2009.

Bryan and Cherry Alexander / Seracs (columns of ice) on a glacier on the East coast of Drygalski Fjord. South Georgia, 2009.

Philippe Clement / Serac on Grand Cornier (3,962m) Pennine Alps, Valais, Switzerland, July 2009

Philippe Clement / Serac the Grand Cornier (3,962m) Pennine Alps, Valais, Switzerland, July 2009

Yva Momatiuk & John Eastcott / Crean glacier with big seracs and ice blocks descending to sea, Antarctic Bay, South Georgia Island

Yva Momatiuk & John Eastcott / Graphic forms of blue ice, seracs and cracks, Fortuna Glacier, Cumberland Sound, South Georgia, Southern Ocean, Antarctic Convergence

Yva Momatiuk & John Eastcott / Graphic forms of blue ice, seracs and cracks, Fortuna Glacier, South Georgia Island, Southern Ocean, Antarctic Convergence

Yva Momatiuk & John Eastcott / Graphic forms of blue ice, seracs and cracks, Fortuna Glacier, South Georgia Island, Southern Ocean, Antarctic Convergance

Colin Monteath / Ice climbing on serac under K2, Godwin Austen Glacier, Karakoram Mountains, Pakistan

Colin Monteath / Seracs on Franz Josef Glacier seen from centennial hut, Westland National Park, New Zealand