The dark depressions in the foreground of the image owe their origin to perennial meltwater ponds on the surface of nearly stagnant crevasse free ice. The depressions fill with summer meltwater then freeze over. Glacier motion subsequently opens a subglacial passage draining away meltwater resulting in a collapse of the ‘ice lid’. Lacuna Glacier, Alaska Range. (6 x 6 cm fuji velvia film, Hasselblad 503CW camera, Carl Zeiss Planar T 80 mm lens), 2011.