The Köfels landslide was a gigantic landslide, known as a sturzstrom, that occurred in the Ötz valley approximately 9800±100 years ago according to radiocarbon dating of trees buried by the event. It involved a 2.5 km horizontal displacement and 800 m vertical displacement of 3.2 km3 of rock and mud along the Ötz valley floor, making it the third largest known sturzstrom.
The British rocket engineer Alan Bond linked this geological evidence to Sumerian astronomical observations and hypothesised an asteroid impact as its cause.
^Ivy-Ochs S, Heuberger H, Kubik PW, Kerschner H, Bonani G, Frank M, and Schlüchter C. (1998). The age of the Köfels event — relative, 14C, and cosmogenic isotope dating of an early Holocene landslide in the central Alps (Tyrol, Austria). Zeitschrift für Gletscherkunde und Glazialgeologie, (34):57–70.
^Sørensena, SA and Bauer, B (15 August 2003). On the dynamics of the Köfels sturzstrom. Geomorphology, 54(1–2):11–19.