Reviewed research article

Avalanches in coastal towns in Iceland

Svanbjörg Helga Haraldsdóttir1,2,3, Esther Hlíðar Jensen2,Leah Tracy2, and Haraldur Ólafsson2,3,4

1Menntaskólinn í Reykjavík (Reykjavík College), 101 Reykjavík,2Veðurstofa Íslands (Icelandic Meteorological Office), 3Faculty of Science, University of Iceland,4Currently at Bergen School of Meteorology, Geophysical Institute, University of Bergen, Norway.

email: svanahh@gmail.com

Abstract — An overview of registered avalanches in the vicinity of 13 towns known to be threatened byavalanches is presented graphically, together with information on weather prior to avalanches at specificlocations. In N-Vestfirðir (NW-Iceland), Central N-Iceland and in Austfirðir (E-Iceland), large avalanchesare generally preceded by heavy precipitation and strong sustained winds from northerly directions. In suchcases, the snow accumulates at the top of the lee slopes. In some cases snow accumulates in gullies when thewind blows parallel to the mountain side and at some locations, snow accumulation is very sensitive to winddirection.

INTRODUCTION

In January and October 1995, catastrophic avalancheskilled a total of 34 people in Súðavík and Flat-eyri (Figure 1) in N-Vestfirðir, NW-Iceland, (Egils-son, 1995a,b, 1996; Ólafsdóttir, 1996; Haraldsdóttir,1998a,b). Property loss was enormous and so wasthe impact on the local society. Since late December1995, Veðurstofa Íslands (Icelandic MeteorologicalOffice) has been responsible for deciding evacuationof residents in Icelandic towns in case of avalanchehazards (Figure 2), hazard mapping and guidingthe work on permanent protection structures againstavalanches (Magnússon, 1998). On the basis ofrecords of avalanches and studies of weather related toavalanches, evacuation plans have been made for indi-vidual towns. After the catastrophic 1995 avalanches,the need for permanent protection measures was re-viewed by Jóhannesson et al. (1996). This led tothe construction of deflecting and catching avalanchedams and supporting structures in avalanche startingzones. Avalanche dams have already been constructed

in five towns, Flateyri, Siglufjörður, Neskaupstaður,Ísafjörður and Seyðisfjörður.

Figure 1. Flateyri after the catastrophic avalanche on26 October 1995, which caused 20 fatalities. Over30 houses were hit by the avalanche – Yfirlitsmynd afFlateyri eftir snjóflóðið mikla 26. október 1995, þarsem 20 manns fórust. Snjóflóðið lenti á rúmlega 30húsum.

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