Orchestra

A glacier, an instrument. Forty-eight glaciers play the map year after year, and each one lights up and sends out a ring of light when it plays. Glaciers that hold play strings, those that looked solid and then collapsed play bells, and those that swing, weak and irregular since the start, play wood. Glaciers that fragment throw glittering crosses.

20,150 glaciers with at least 20 observed years, 48 of them playing. Each plays four of its own measures: the position of its snow line, its snow cover, its snow cover inside the reference glacier surface and the gap to that surface.

Sound and image come from the same list of 8,714 notes.

Each year each glacier plays a short phrase made from its measures, on strings, wood or bells, higher in the north. Fragmentation puts notes out of tune and breaks them. The scale darkens as the region drifts from its reference, and a low drone follows the average snow.