Avalanches and landslides occur when a mass of snow or earth materials topples, falls, rolls, or slides down an incline due to gravity. Snow avalanches are mass movements of snow. Common types of mass movement of earth materials in Iceland are rockfalls, debris flows, earthflows, and rockslides.
Avalanches and landslides in Iceland have caused many deaths and serious accidents over the centuries, as well as enormous economic damage. Casualties and damage to farms and buildings as early as the tenth century are mentioned in historical sources. Some records clearly describe landslide events, but others could refer to snow avalanches. In 1118, a snow avalanche in West Iceland swept away five men, all of whom died. This is the earliest record of what can reliably be identified as a fatal snow avalanche.
In the twentieth century, there were 208 deaths in Iceland due to avalanches and landslides. Of these, 166 died in snow avalanches. Landslides resulted in 42 deaths: 24 due to rockfalls and 18 due to other types of landslides. At least 59 persons were injured in landslides (55 in rockfalls and 4 in other types of landslides).
The tragic avalanches that fell on the Icelandic villages of Súðavík and Flateyri in January and October 1995 claimed 24 lives and destroyed many homes. These disasters opened the eyes of the general public to the unacceptably high risk that snow avalanches and landslides pose for a number of rural communities. There has since been a sea change in avalanche and landslide management and prevention.
Risk assessment provides an important basis for actions aimed at minimising the danger for communities. The Icelandic Meteorological Office oversees risk assessment and all necessary research and monitoring of snow and meteorological conditions. Since 1995, risk assessment has focused mainly on several communities where the avalanche and landslide risk is very high. Preventive action may include preparation of evacuation plans, erection of defence structures (such as avalanche nets), and construction of protective earthworks. Other measures may include changes to zoning and land use, and buying up of homes in affected areas.
Work has recently started on assessing avalanche and landslide conditions in rural areas. This research focuses on snow avalanche and landslide risks for farms and residential buildings in the countryside, as well as for cottages. The IINH has participated in numerous risk assessment projects in collaboration with the Icelandic Meteorological Office, mapping landslides and investigating landslide risks.