Flommer og flomskred i Gudbrandsdalen i et værmessig og klimatisk perspektiv (original) (raw)

2016, Gård og utmark i Gudbrandsdalen - Arkeologiske undersøkelser i Fron 2011-2012

The archaeological investigations in the mid part of Gudbrandsdalen in 2011 and 2012 revealed a number of flood/avalanche horizons, of which «Forrskredet» (ca 350–200 BC), «Gammelofsen» (ca 50–1 BC), and «Merovingertidsofsen» (ca AD 600–800) were recognised as the major events at the investigated sites. Local topography and weather conditions (such as extreme weather events) and more long-term climatic trends were most likely the triggering factors for these events. During the time interval for Forrskredet, glaciers in Jotunheimen were in an advanced position, winter precipitation in mountains in western Norway (Jostedalsbreen) was relatively high, and summer temperatures in Scandinavia, as reconstructed from tree rings, were relatively high. Gammelofsen occurred during a period with relatively small glaciers in Jotunheimen as winter precipitation was increasing in western Norway and summer temperatures were rising in Scandinavia. During Merovingertidsofsen, glaciers in Jotunheimen were in an advanced position, winter precipitation was rapidly increasing in western Norway, and summer temperatures were relatively low in Scandinavia. The prehistoric flood and avalanche events in Gudbrandsdalen, such as the subsequent historic flood events, in particular «Storofsen» (1789) and «Storflaumen» (1860), certainly had a severe impact on settlement and farming.