The river outlet at the eastern margin of Skeiðarárjökull. The mountains in the background are Krossgilstindur and Færnes. Click for further information.

A small jökulhlaup in Gígjukvísl

Glacier outburst flood

27.3.2014

A small jökulhlaup (glacier outburst flood) is now occurring in the river Gígjukvísl. The event originates from the subglacial lake Grímsvötn. The event is expected to be small, with maximum discharge on the order of magnitude 1000 cubic meters per second. The maximum of the flood is expected to be around the end of the week.

Conductivity measurements indicate a considerable increase of geothermal contribution to the water of the river. Simultaneously, the ice on the subglacial lake has lowered and seismic tremors have increased. These tremors are a consequence of the jökulhlaup and not indicative of volcanic activity.

Hydrogen sulphide is released from the floodwater as it drains from the Vatnajökull ice-cap. The gas is particularly potent at the river outlet at the ice margin, where concentrations may reach poisonous levels.

Otherwise, no threat is expected from this flood, which does not exceed high river discharge at summer. The road and bridge are safe.

A small jökulhlaup

The bridge across river Gígjukvísl, 27 March 2014 at 08:00, view to the WNW and the mountain in the background is Lómagnúpur. Photo: Njáll Fannar Reynisson.

The river Skeiðará changed its course in 2009 and now runs due west along the margin of Skeiðarárjökull outlet glacier and contributes to Gígjukvísl. For orientation, see a map from ja.is which shows road nr. 1, Gígjukvísl bottom left and Skeiðará top right.