Real estate development and urbanization that led to “unusually powerful erosion” in and around a local creek is what set off last winter’s deadly mudslide in a residential area of Ask in Gjerdrum, north of Oslo. Ten people were killed in the terrifying slide that destroyed an entire neighbourhood in the middle of the night.
A state commission set up to investigate the cause of the slide issued its conclusions on Wednesday. Lots of construction in an area known for clay-like earth had affected the natural flow of the creek known as Tistilbekken, which runs through the area. Erosion tied to development of the area around the creek over the past 14 years worsened an already unstable slope. Heavy rains in the fall of 2020 ultimately caused the ground to give way just before New Year’s Eve.
The commission concluded that if the creek had been secured against erosion, the slide probably wouldn’t have occurred. It remained unclear who would have been responsible for such security measures: the developers, operators of a local golf course, the landowner or the municipality.
After the first concerns were lodged in 2008, local officials ordered evaluations of the area and sought professional advice. “Some of it was followed, some of it was not,” said commission leader Inge Ryan at a press conference Wednesday. Local officials have otherwise been praised for their openness and response to the tragedy.
“We now of course wish we’d done more with that creek,” current Gjerdrum Mayor Anders Østensen told reporters. The municipality does not own the land in question.