Increased discharge and significant gas pollution in Múlakvísl

The glacial outburst flood that began in Múlakvísl on 18 August is ongoing. Since yesterday, electrical conductivity and discharge in the river have increased, and gas pollution continues to be detected in the area. Yesterday evening, electrical conductivity rose fairly sharply and now measures just over 500 µS/cm, which is unusually high compared with recent glacial outburst floods in the river. Conductivity last reached a similar level during the glacial outburst flood in July 2017, when it peaked at 580 µS/cm.

So far, the water level in the river has not risen significantly. However, webcam footage shows that the river has spread across a wider area, indicating that discharge has increased.

Several geothermal areas are known to exist beneath Mýrdalsjökull. Meltwater drains continuously from these areas, and the local topography determines whether or not it accumulates. The amount of water that collects in these subglacial lakes before an outburst occurs varies, as does the rate at which they drain.

Glacial outburst floods of this magnitude are well known in Múlakvísl. This event is accompanied by significant gas pollution. People are therefore advised not to remain near the river or close to where it emerges at the glacier margin. The calm weather in recent days also increases the risk of gas accumulating in depressions. Anyone experiencing symptoms such as irritation of the nose or eyes should leave the area immediately.

The Icelandic Meteorological Office is closely monitoring developments and remains in direct contact with Civil Protection.