Grímsvötn lakes flash flood has begun
The Icelandic Meteorological Office says that in recent days, slowly increasing flash turbulence has been detected on the seismometer on Mt Grímsfjall. This indicates that a glacial flash flood has begun from Grímsvötn lakes.
Glacier flash floods from Grímsvötn lakes emerge from Skeiðarárjökull glacier and flow into Gígjukvísl river. The flows are usually slow-growing and it can take several days until the first signs of flash water are measured at the hydrological station in Gígjukvísl river and again several more days until the flow reaches maximum flow, the Icelandic Meteorological Office reports in a statement.
"There has been some precipitation in the South-East and further precipitation is expected today and the next few days. The precipitation may make it more difficult to detect the first signs of the flash flood in Gígjukvísl river," it also says.
Civil Protection has declared a level of uncertainty due to a glacial outburst flood from Grímsvötn lakes. Photo/Civil Protection
Last glacial outburst exactly one year ago
The last glacial outburst from Grímsvötn lakes occurred almost exactly one year ago and has occurred from there at approximately one-year intervals since November 2021. Before that, the intervals between outbursts were somewhat longer and the last outburst before 2021 was in 2018, according to the Icelandic Meteorological Office.
According to measurements by the Icelandic Institute of Earth Sciences, the water volume in Grímsvötn is now estimated to be about 0.25 km3, which is comparable to or almost what was in the lakes before the last outburst. This amount of water is almost a third of what was in the lakes before the flood at the end of 2021.
No contact with GPS device
It is said that the Institute of Earth Sciences' GPS device on the ice shelf in Grímsvötn lakes cannot be contacted, making it more difficult to assess how quickly the water is flowing from the lakes and down the channel under Skeiðarárjökull glacier, but turbulence measurements on Mt Grímsfjall provide indications of the development of the flood.
The flood should not affect structures
"If we assume that the scenario in this flood will be similar to the last floods, it can be assumed that the maximum flow from Grímsvötn lakes will probably be at the end of this week. The maximum flow in Gígjukvísl river at Highway 1 will be reached about 1-2 days later. Given the amount of water that has accumulated in Grímsvötn lakes, it is likely that the maximum flow will not exceed 1,000 m3/s." "The maximum flow in Gígjukvísl river at Highway 1 is expected to be similar to the maximum flow from Grímsvötn lakes. The flow should therefore not have any impact on structures, such as roads and bridges," the announcement says.