The flow in Gígjukvísl river has increased significantly due to the glacier outburst flood (jökulhlaup) which began in Grímsvötn volcano on Monday, ruv.is reports.
Conductivity measurements indicate a considerable increase of geothermal contribution to the water of the river, according to Bergur Einarsson at the Icelandic Met Office. Simultaneously, the ice on the subglacial lake Grímsvötn has lowered and tremors have increased as a consequence of the flood. The Met Office emphasizes that the tremors are not indicative of volcanic activity.
According to preliminary results from the Icelandic Met Office, the flow was less than 500 cubic meters per second yesterday morning, which is less than high river discharge during summer. The flood is expected to reach its peak today or tomorrow.
Bergur pointed out that hydrogen sulfide is released from the floodwater as it drains from the Vatnajökull icecap. The gas is particularly potent at the river outlet at the ice margin, where concentrations may reach poisonous levels, Bergur said. High concentrations can damage the mucous membranes of the eyes and respiratory tract.
The flood does not pose a threat to the road on Skeiðarársand or the bridge over Gígjukvísl river. The bridge was replaced when it was swept away during a huge glacial flood in 1996.
