Corresponding thermal image showing temperature of the debris cover over the glacier terminus and the surface temperature of the lake. The brighter colours in the thermal image are warmer temperatures, while the darker colours are cooler. Surface water at the centre was 4.4°C, while the surface temperatures captured in the field of view (including the lake and the surrounding rock) ranged from 3.3°C to 29.1°C. [Image: Andrew Lorrey, NIWA]