ABSTRACT. Avalanche hazard is a threat to many residential areas in Iceland. In 1995 two avalanche accidents, causing a total of 34 fatalities in areas thought to be safe, prompted research on avalanche hazard assessment. A new method was developed, and in 2000 a new regulation on avalanche hazard zoning was issued. The method and regulation are based on individual risk, or annual probability of death due to avalanches. The major components of the method are the estimation of avalanche frequency, run-out distribution and vulnerability. The frequency is estimated locally for each path under consideration, but the run-out distribution is based on data from many locations, employing the concept of transferring avalanches between slopes. Finally the vulnerability is estimated using data from the 1995 avalanches. Under the new regulation, new hazard maps have been prepared for six of the most vulnerable villages in Iceland. Hazard zones are delineated using risk levels of 0.2610^4, 0.7610^4 and 2610^4 a^1, with risk less than 0.2610^4 a^1 considered acceptable. When explaining the new zoning to the public, a measure of annual individual risk that allows comparison with other risks in society has proven advantageous.

Snow avalanches have caused many catastrophic accidents and severe economical losses in Iceland since the country was settled in the ninth century. The first reported avalanche accident dates back to 1118 when a snow avalanche killed 5 people in western Iceland. Altogether about 680 deaths by avalanches have been reported in Iceland since then. Unaccounted deaths may be assumed to have been several hundreds, especially during two gaps a total of 250 years in the written records before 1600. Since 1901 altogether 193 persons have been killed in avalanche and landslide accidents in Iceland. Catastrophic avalanches in the villages Súðavík and Flateyri in 1995, which killed 34 people and caused extensive economic damage, have totally changed the view regarding avalanche safety in Iceland. These avalanches made it clear that a substantial number of people in several Icelandic towns and villages live in areas where avalanche risk is unacceptable. Although extensive evacuations may be used to reduce the risk to some extent, this can only be viewed as a temporary measure. Avalanche protection measures or land use changes are necessary for a permanent solution to this problem. Direct economic loss due to avalanches and landslides in Iceland in the 26 year period between 1974 and 2000 is about 3.3 billion IKR (41 million USD). The total cost of defence structures, which have been constructed or are under construction in the towns Flateyri, Siglufjörður and Neskaupstaður since 1995, together with the cost of relocation in endangered areas is about 2.5 billion IKR (31 million USD). The loss includes insurance payments and the cost of rescue and relief operations due to avalanches in towns and villages, and insurance payments due to avalanches in rural areas (damages to farm buildings, power and telephone lines and ski lifts). Other economic losses, especially due to avalanches in rural areas, are substantial, but may be assumed to be much smaller than the loss estimated above. A total of 52 people have been killed by avalanches in buildings, at work sites or within towns during the period 1974 to 2000, while 17 people have been killed by avalanches and landslides outside populated areas during the same period. If the death of a person in an avalanche or landslide accident is included in the economic loss as 100 million IKR (1.2 million USD) per fatal accident, the total cost of avalanche and landslide accidents in Iceland in the last 26 years together with the cost of avalanche protection measures is more than 13 billion IKR (162 million USD). 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.