Jökull - 01.12.2006, Blaðsíða 3

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 by
avalanches is presented graphically, together with information on weather prior to avalanches at specific
locations. In N-Vestfirðir (NW-Iceland), Central N-Iceland and in Austfirðir (E-Iceland), large avalanches
are generally preceded by heavy precipitation and strong sustained winds from northerly directions. In such
cases, the snow accumulates at the top of the lee slopes. In some cases snow accumulates in gullies when the
wind blows parallel to the mountain side and at some locations, snow accumulation is very sensitive to wind
direction.
INTRODUCTION
In January and October 1995, catastrophic avalanches
killed 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 was
the impact on the local society. Since late December
1995, Veðurstofa Íslands (Icelandic Meteorological
Office) has been responsible for deciding evacuation
of residents in Icelandic towns in case of avalanche
hazards (Figure 2), hazard mapping and guiding
the work on permanent protection structures against
avalanches (Magnússon, 1998). On the basis of
records of avalanches and studies of weather related to
avalanches, 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 to
the construction of deflecting and catching avalanche
dams and supporting structures in avalanche starting
zones. Avalanche dams have already been constructed
in five towns, Flateyri, Siglufjörður, Neskaupstaður,
Ísafjörður and Seyðisfjörður.
Figure 1. Flateyri after the catastrophic avalanche on
26 October 1995, which caused 20 fatalities. Over
30 houses were hit by the avalanche – Yfirlitsmynd af
Flateyri eftir snjóflóðið mikla 26. október 1995, þar
sem 20 manns fórust. Snjóflóðið lenti á rúmlega 30
húsum.
JÖKULL No. 56 1