Háalda is a small part of a vast flood plain where glacial floods from Öræfajökull used to run. It was declared a protected natural monument in 1975, and stands in witness to these great glacial floods.

The depression at Háalda is one of two kettle holes that were formed when two large icebergs ran aground tightly together in the sand dune. When icebergs lay on the surface of the flood plain they would melt in a matter of months, while icebergs that were buried in the sand could take decades to melt, leaving depressions of this kind. These are most commonly referred to as kettle holes, but the locals also have their own terms for them, which translate to "pits" and "iceberg dents”.

Volcanic eruptions under a glacier are often accompanied by sudden glacial outbursts or jökulhlaup. This has been the case for Öræfajökull, which rises to a height of over 2000 meters and is covered with a glacier at the top. In an eruption, the hot magma melts a large amount of ice in a short time causing a sudden jökulhlaup. The jökulhlaup that followed the eruptions of Öræfajökull in 1362 and 1727 flowed down steep slopes that mixed water, silt, ash and rock fragments from the glacier itself. The jökulhlaup following the 1727 eruption mostly flowed down the course of Kotár, but also Grænafjallsgljúfi. At the head of the course of Kotárgljúfur and before the flow dissipated, it was like a large river measuring about 220-280m wide and 20m deep. As the run spread and flowed south to the sea, it deepened and ice and silt settled on the floodplain. After, the floodplain was covered with icebergs and ice cliffs.

Háalda

Fræðsla

Jökulhlaup from Öræfajökull

Destinations

Falljökull

Sandfell