Field observations and laboratory experiments for evaluating the effectiveness of avalanche defence structures in Iceland. Main results and future programme

Tˇmas Jˇhannesson
In: Proceedings of the International Seminar on Snow and Avalanches Test Sites, Grenoble, France, 22-23 November 2002, Florence Naaim-Bouvet, ed., 99-109. Grenoble, Cemagref, 2003

Abstract

Catastrophic avalanches in the villages S˙­avÝk and Flateyri in 1995, which killed 34 people and caused extensive economic damage, have totally changed the view regarding avalanche safety in Iceland. The Icelandic government has drawn up a plan to construct avalanche protection measures for hazard areas and/or to purchase endangered property in order to reduce the death toll and the economic losses caused by avalanches in the future. Protection measures have up to now been constructed for three avalanche paths in north-western, northern and eastern Iceland and settlements in two villages have been relocated to safer areas. Deflecting dams in the villages Flateyri and Siglufj÷r­ur have already been hit by snow avalanches on four separate occasions since the construction of the dams in 1997-1999. The avalanches were in all cases successfully deflected away from the settlements. Data about these avalanches provide interesting information about the dynamics of snow avalanches that hit deflecting dams. Laboratory experiments, that were performed as a part of the design of retarding mounds and a catching dam for the village Neskaupsta­ur in eastern Iceland, have provided new insights into the dynamics of avalanches that hit retarding structures. Plans have been made for the installation of instrumentation to measure the speed of avalanches that hit the deflecting dams at Flateyri.


Updated: January 2004. Comments: tj@vedur.is