by Hallgeir Elvehøy, January 5, 2022
After a fairly dry winter at Jostedalsbreen, the 2021 summer at Jostedalsbreen was warmer than average, and consequently the summer balances were larger than average.
At Austdalsbreen on the northern part of Jostedalsbreen, all the winter snow melted. After year 2000, this has happened more than every second year. The annual balance for 2020/21 was -1.7 m w.e., well below the 1991-2020 average of -0.6 m w.e. per year.
At Nigardsbreen about 5 meters of snow melted on the glacier plateau, resulting in an equilibrium line altitude (ELA) around 1635 m a.s.l. The annual balance for 2020/21 was -0.5 m w.e., which is below the 1991-2020 average of 0.0 m w.e. per year. At the glacier tongue at an altitude of about 600 m a.s.l., 9 meters of ice melted between May and October 2021.
The summer balances at Austdalsbreen and Nigardsbreen were 123 % and 105% of the 1991-2020 averages, respectively.
The dominantly negative mass balance at Jostedalsbreen the last 20 years has resulted in a marked retreat of the outlet glaciers. Five observed glaciers have retreated on average 520 meters during this period. In 2021, the observed retreat varied between -2 meters at Vetle Supphellebreen in Fjærland and -130 meters at Austerdalsbreen in Veitastrond. The average for seven outlet glaciers was -32 meters.
Mass balance stake on Austdalsbreen (1475 m a.s.l.), 27 August 2021 (photo: Jostein Aasen/NVE).