Háalda was protected as a natural monument in 1975. The area is a moraine between Sandfell and Hof. Glacial sediment formed in a glacial outburst in a 1727 eruption in Öræfajökull. This phenomenon is a typical dead-ice landscape. The moraine’s kettle hole is a glacial imprint.

The natural monument covers an area of 4.9 ha.