Figure 3: Model domain in the central Southern Alps of New Zealand.

The map shows the location of major glaciers, mean glacier mass balance (1972–2011), surface debris cover and pro-glacial lakes. The Southern Alps contain more than 3,000 glaciers, but the greatest volume of glacier ice in New Zealand is located within our model domain at 43°S, approximately centred on Aoraki/Mt Cook, New Zealand’s highest mountain (3,724 m). Mass balance (metres of water equivalent per year) is shown in red (net melt) and blue colouring (net accumulation). Very large gradients in glacier mass balance exist within the model domain, depending on glacier elevation and location with respect to the major drainage divide (main divide). Franz Josef and Fox glaciers to the west and north of the main divide each show snow accumulation rates of ∼10 m, and melt rates of ∼20 m of water equivalent per year. Surface debris covers the lower portion of many glaciers including the Tasman, Hooker, Mueller and Murchison glaciers. Terminal lakes have grown rapidly at these glaciers since the 1980s.