Report from brake measurements in 2017
Vetle Supphellebreen bucked the trend and advanced in 2017, while Haugabreen retreated.
At the front of Vetle Supphellebreen in early November 2017. Photo: Pål Gran Kielland.
For us glacier enthusiasts, it's always good news when a glacier grows and advances. Vetle Supphellebreen advanced for the third year in a row, by almost 2 meters in 2017. We started measuring the front position of the glacier in 2011 and the glacier showed an eighteen-meter advance in the first few years. During the measurement period, the glacier has advanced by a total of 4 meters, or in other words remained stable. An excess of snow during the measurement period may explain the development of Vetle Supphellebreen. If we look at the Meteorological Institute's weather and climate data, the measuring station at Norwegian Glacier Museum has registered precipitation amounts above normal in the period 2011-2017. Large amounts of snow may be part of the explanation for the glacier's advance in recent years. Along with factors such as temperature, latitude, height above sea level, terrain (steepness and solar radiation) and proximity to the sea (maritimeity), precipitation is part of a complex interaction that leads to the formation and change of glaciers. In particular, it is the relationship between winter precipitation and summer temperature that controls the glacier's balance from year to year.
Haugabreen after fresh snowfall in November 2017. Photo: Pål Gran Kielland.
Haugabreen set a personal negative record when it retreated 18 meters in 2017. Since we started measuring this glacier, it has decreased by a total of 53 meters. There is also an increase in precipitation here when we look at weather data from nearby measuring stations, but the precipitation has clearly not been enough to slow down the melting. In addition, it must be remembered that the glacier's reaction time to changes in climate has been reduced. Since glaciers are mainly governed by winter precipitation and summer temperature, changes in these climate parameters will be reflected in the glacier. A lot of snow and/or low temperatures cause glaciers to grow, while little snow and/or high temperatures cause glaciers to melt.
Front changes show how the length of the glacier changes from year to year, and are a picture of how the glacier volume changes over time. The changes that can be seen on a glacier front are a slow reaction to changes in mass balance. The reaction time of glaciers depends on factors such as their length, steepness and friction with the ground. Around Jostedalsbreen, the reaction time of the outlets generally varies between 3 and 30 years.