Large quick clay slides in Norway

Quick clay slides are typical in Norway and Sweden. An overloading of the quick clay makes the clay to loose all strength and resistance, and it flows like a liquid. Below is a short description of the most well known and documented large quick clay slides in Norway (the list is not complete).

Published 08.02.2023

Quick clay slide at Byneset in Trondheim 2012

Børsa in 1254, 1822 and 1823
Buvika in 1702 and 1864
Kristiansten fortress in Trondheim in 1625, which created Duedalen (a New valley). 20 casualties. At least 3 People were killed in a New slide at about the same spot in 1634.
Tiller-slide 7th March 1816 in Tiller soth-west of Trondheim. Ruined the church and several farms with 500 dekar Farmland, mills, sawmill and bridges. 15 people and unknown number of livestock were brought into the river Nidelva and died.
Skjea in Sørum, north-east of Oslo, 15th April 1768. 16 People were killed when the farm was struck by aquick clay slide. Nine of them were found in the river Rømua. Seven People survived, but several of them severely injured. 26 dwellings and a number of livestock were taken by the slide debris.
Verdal in 1893. This is the largest and most severe quick clay slide in Norway ever. 55 million m3 slid out and 116 People were killed.
Kogstadfallet the night between 20th and 21st October 1924, in Gjerdrum. Slide area of 10–12 acres, and in addition and area of about 10 acres was flooded with slide masses and debris. One person diappeared and was never found and a woman was severely injured and deceased after a few years. Several farms and 1600 m road were detroyed.
Lade in Trondheim in 1944. Four People were killed in a quick clay slide in densely built-up area.
Bekkelaget in Oslo in 1953. 5 People were killed in the quick clay slide that took part of the main railway track into Oslo from Sweden in the south, and 100 meters of the main road into Oslo, Mosseveien.
Sokkelvika in 1959 on the west side of Reisefjorden in North-Troms started on the seafloor and propagated in on land. Nine People were killed.
Skjelstadmark in Stjørdal (North of Trondheim) 14th September 1962. Two million m3 slid out. A two year old boy was killed.
Trøgstad in Østfold, South of Oslo. Two slides, in 1967 and 1974. In 1967 1 million m3 slid out and four people were killed.
Rissa 29th April 1978 was the largest quick clay slide that hit Norway in he 20th Century. 5–6 million m3 clay slid out from an area of 330 dekar and left a slide scar of 1,5 kilometers. Over 20 dwellings and farms were taken by the slide, and one person was killed. The slide ran out into the lake Botnen and created a small tsunami of 3 meters.
Balsfjord in 1988. Two People were killed.
Finneidfjord in Nordland 1st June 1996. Two dwellings were taken and about 400 meters of the E6 slid out into the fjord. Four People were killed in the slide.
Kattmarka, Namsos, 13th March 2009. Quick clay slide in connection with raod work. Large housing area slid out into the sea shore. No casualties.
Lyngseidet, Troms 3rd September 2010. A relatively large quick clay slide occured by the sea shore, after deposistion of soil masses. The slide propagated backwards and took three dwellings and the main oad through Lyngseidet. Skredet forplantet seg bakover og tok med seg flere bolighus og hovedveien gjennom Lyngseidet. No casualties.
Byneset in Trondheim 1st January 2012. A several hundered meters long soil slide (see the large picture on top) occurred along a creek at Byneset in Trondheim munisipality. Ingen No casualties, but about 50 People were evacuated for several days.
Sørum 10th November 2016 took three forest worker. One of them was found dead, the two others were never found.
Alta June 3, 2020. A large quick clay slide started at the sea side at Kråknes in Alta. Several houses and cabins were washed out to sea. There were no fatalities and no injuries.
Gjerdrum, early morning 30th December 2020, took several dwellings in the housing area Nystulia close to Ask centre in Gjerdrum. Ten people were killed, including a pregnant woman.