Meltwater exits the glacier in outlets at the snout to form glacial rivers. Glacial rivers are loaded with debris, sand and very fine sediments suspended in the water and make it appear cloudy, sometimes called glacial milk. Due to ever-changing landscapes at glacier margins, rivers can easily change their course, leaving dry river beds and old bridges that have outlived their use. For example, the longest bridge in Iceland over the Skeiðará river has now been dismantled after the river changed course into the Gígjukvísl river in 2009.

Rivers that have changed course since early 20th century (from Halldór Björnsson et al., 2018):

Skeiðará into Gígjukvísl 1929, 1991 and 2009

Veðurá into Stemma 1930–1940

Heinabergsvötn into Kolgríma 1954

Breiðá into Fjallsá 1954

Skaftá no longer flows into Langisjór 1966

Stemma into Jökulsárlón 990

Branch of Skaftá into Hverfisfljót 1991, 1994 and probably 2011

Sæluhúsavatn into Gígjukvísl ca 1992

Outlet of Breiðá moved in 2002

Neskvísl into Svínafellsá 2007

Hrútá into Fjallsárlón ca. 2007

Austurfljót into Suðurfljót 2008

Leirá á Mýrdalssandi into Skálm 2013

Súla into Gígjukvísl 2016

Eystri Kvíá into Kvíá, timing uncertain

Skráma into Svínafellsá, timing uncertain

In the 1940s, a bridge was constructed over Heinabergsvötn river, but shortly after its completion, the river moved westwards and merged with the neighbouring river, Kolgríma. The bridge still spans a dry riverbed. Photo: Snævarr Guðmundsson, August 16^th 2017. Lower image: River Heinabergsvötn in 1948. Photo: Skarphéðinn Gíslason.

Aerial view of the foreland of Hoffellsjökull. Photo: Snævarr Guðmundsson, August 17^th 2006.

Braided rivers on Skeiðarársandur. Photo: Oddur Sigurðsson.