[1] At Selfjall, about 10 km (6.2 mi) east of the village Vík í Mýrdal, the Ring Road goes across a bridge over the Múlakvísl.

As increasing water levels of this river are an important indicator of Katla's upcoming volcanic eruptions, it is closely monitored.

This showed volcanic activities under the glacier, which in turn initiated the jökulhlaup.

[1] On 9 July 2011, another jökulhlaup occurred, which was already anticipated hours and days before because of a series of quakes at up to 10 km (6.2 mi) depth in the Katla region.

A water level early warning system prompted the closing of the bridge and surrounding area, and no one was harmed.