Publisert 17.09.2019 , sist oppdatert 22.02.2021

Glacier lakes

Background

Glacier lakes are sensitive to climate change and can cause glacier-related hazards. Glacier lakes in mainland Norway have long posed a threat due to frequent outburst floods. A jøkulhlaup or Glacier Lake Outburst Flood (GLOF) is a sudden release of water from a glacier. The water source can be a glacier-dammed lake, a pro-glacial moraine-dammed lake or water stored within, under or on the glacier. Sentinel-2 imagery can be used to survey locations with previously registered GLOFs or detect new possible GLOF sites. Having an updated glacier lake outline dataset with identified glacier and moraine-dammed lakes can be used as the basis for investigation of future changes in lakes on a local or a national scale.

Sentinel-2 imagery showing the glacier dammed lake Demmevatnet in August 2019. The lake was emptied on August 24.

Data glacier lake outlines in mainland Norway

Two glacier lake outline datasets have been derived in the Copernicus Glacier Service project. They supplement previous outlines derived in the CryoClim project.

  • Glacier lake outlines 2014: Mapping of the lake outlines was conducted using manual digitisation from Landsat imagery from 2014. Glacier lakes were defined as water bodies that either intersected or were within a distance of 50 m of the glacier outline of the previous inventory (1999-2006). Download data 2014
  • Glacier lake outlines 2018: Mapping of the lake outlines was conducted using optical Sentinel-2 satellite imagery from 2018 by calculating the Normalized Differential Water Index (NDWI), applying a threshold and manually correcting outlines when necessary. The lakes were categorized according to the nature of the contact with the ice interface. Sites where lake emptying (jøkulhlaup) events had happened were identified. A NVE report describes the dataset (Nagy and Andreassen, 2019). Download data 2018

The lake inventory datasets are available for viewing at:

NVEs digital glacier BreAtlas at: https://gis3.nve.no/link/?link=breatlas 
(per now 2014 as Bresjo_2014, the new dataset will be added later) 

xGeo at: http://satellitt.xgeo.no/index.html?p=bre (the lakes of 2018, bresjøer)

References
-Winsvold, S.H. and L.M. Andreassen.: Glacier Lake Outline – Norway, v1.0. 2012. NVE. http://arcus.nve.no/data/bre/GLO/zip/. Delivered by CryoClim service.  (GLO1998-1997 & 1999-2006)
-Andreassen, L.M. (ed.), G. Moholdt, A. Kääb, A. Messerli, T. Nagy and S.H. Winsvold. 2021. Monitoring glaciers in mainland Norway and Svalbard using Sentinel. NVE Rapport 3-2021, 94 p. (GLO2014)

Nagy, T. and L. M. Andreassen. 2019. Glacier lake mapping with Sentinel-2 imagery in Norway. NVE Rapport 40-2019, 54 s.

Further information on glacier lakes

See more information on Jokulhlaups/GLOFs in Norway: https://www.nve.no/hydrology/glaciers/jokulhlaup-glof/

Overview of registered glacier lake outburst floods in mainland Norway. Information about registered events are given as well as photos of the affected glaciers.http://glacier.nve.no/viewer/GLOF/en/