Landslides fall all year round but are most common in the fall and in the spring. The reason can be traced to the fact that great rain is most imminent in the fall and in the spring, there is the spring thaw. Alongside this they occur most seldom in late winter, especially if the earth is frozen. Contrastingly, snow avalanches are more likely to fall in winter and they are most likely to fall during the time between January and March (Ólafur Jónsson, 1992, 43). Landslides are common in Iceland and the cause is among other things due to weather conditions, lithology, soil erosion and soil on mountainsides as well as the landscape (The Icelandic Institute of Natural History, Landslides). Landslides can fall wherever there are slopes and do fall all around the country. It is not always evident what causes the landslides and the reasons can be multifarious. Canyons and mountainsides can even be so unstable that it only takes a little bit of rain or temperature change in order for a landslide to start falling (Jón Kristinn Helgason and Harpa Grímsdóttir, 2014). Landslides are categorised as falling rocks, earthslides, rock-faceslides, rockslides, slow-rappelling-down-hunks of matter and mudslides. The matter that can be carried down by the landslides can be soil, scree, or a piece of bedrock. Mud- and landslides often fall from channels in mountainsides. Even though the reasons for landslides can vary, most landslides in Iceland are caused by much precipitation or great thawing (The Icelandic Institute of Natural History, Landslides). When the soil is very dry it sucks in all precipitation. When there is much precipitation in a short amount of time, the water does not manage to trickle through the soil and find normal channels and searches instead for a hard rock face under the saturated soil, makes the rock face wet and slippery and trickles by it (Ólafur Jónsson, 1992, 75). It is believed that in the 20th century all together 42 people lost their lives because of landslides and at least 59 more were injured. In comparison during the same period 166 people lost their lives to snow avalanches (The Icelandic Institute of Natural History, Avalanche).
Ólafur Jónsson. (1992). Landslides and avalanches (Volume 1, 2nd Edition). Reykjavík: Skjaldborg publishing house.
The Icelandic Institute of Natural History. Landslides. Retrieved from: https://www.ni.is/jord/jardgrunnur/skridufoll.
The Icelandic Institute of Natural History. Avalanche. Retrieved from: https://www.ni.is/jord/natturuva/ofanflod.
Jón Kristinn Helgason and Harpa Grímsdóttir. (2014, June 3rd). About landslides. Icelandic Meteorological Office. Retrieved from: https://www.vedur.is/ofanflod/frodleikur/greinar/nr/2901.