Scientists monitoring the Rhône Glacier in Switzerland are measuring rapid ice loss after a summer of high temperatures.
They track meltwater, use dye to follow its flow and measure how much the surface has dropped.
Swiss glaciers lost 5.5% of their remaining ice volume in 2026, the second-largest annual decline on record. Persistent summer heat waves and a dry winter with little snowfall left the ice with less protection and caused melting to start earlier.
Some glaciers have lost between 2.5 and 4 metres in thickness this year, with losses of up to 10 metres recorded on some glacier tongues.