Two views of the Ekstroem Ice Shelf, East Antarctica (above and above right). The upper surface near its edge is marked by a knobbly icy surface – the result of storm waves throwing up spray that freezes as a crust on the surface. MH

The above photograph illustrates the shelf edge, marked by an undercut cliff, rising about 30 m above water level, while a few more hundred metres of cliff extends below the water-line. MH