A 20-meter wide landslide struck Carl Berners Plass in Oslo on Sunday afternoon. Hundreds of residents were evacuated from their homes as rocks and debris tumbled down the hillside.
Oslo municipality dispatched geologists to assess the area Sunday evening. Their evaluation led to continued evacuations for buildings above and below the landslide zone.
Another small rockslide occurred from the same area Monday morning, according to city officials.
Geologist Jaran Wasrud from the Norwegian Water Resources and Energy Directorate participated in the initial assessment. He explained they first need to understand the slope's stability and composition.
At 4:15 PM Monday, municipal geologists planned to conduct another inspection of the landslide area. Officials stated they need to further evaluate safety concerns.
Authorities have ordered additional investigations from the Norwegian Geotechnical Institute. They will conduct laser scanning to create a 3D image of the mountainside.
Wasrud noted that the existing safety netting appeared designed to catch smaller rocks and debris. The large block that broke loose exceeded what such netting typically contains.
He described the area as an older rock cutting, likely blasted out to prepare the building site before housing construction. Most slopes in Oslo are partially human-made, he added.
The student housing at Carl Berner was constructed in 2002, followed by the Sukkertoppen residential block. The student organization SiO completed major renovations and added extra floors in 2011.
A 2009 risk assessment by consulting firm Multiconsult identified falling rocks and larger landslides as the primary hazards in the area. The report stated risks could be reduced to acceptable levels using known safety measures.
In 2021, Oslo's planning department notified SiO about potentially dangerous conditions in the rock face near the student housing. SiO cleared loose material but conducted no additional safety work, stating the slope was already well-secured with bolts and netting.
When building in steep terrain, developers must document area stability against landslides. Oslo municipality verifies this documentation exists.
The board chairman of Sukkertoppen housing cooperative said residents won't know when they can return home until Tuesday at earliest. Geotechnical experts are currently measuring and requesting access to building plans.
He expressed previous confidence in the safety measures, noting they appeared solid. The landslide began on SiO's property before spreading to their area.
SiO announced they're working with the municipality on solutions for displaced students. They will pay 1,000 kroner ($95) per evacuated resident to cover immediate needs like toiletries.
Students don't need to submit receipts for these purchases. The municipality maintains evacuation centers and overnight accommodation through Tuesday night.
Wasrud explained such limited rockfalls usually conclude relatively quickly once the main masses break loose. Smaller rocks may still fall afterward, requiring continued monitoring.
He noted many landslide events occur in Norway annually, but most happen outside populated areas. This landslide was large and therefore dramatic.
The situation reveals the ongoing challenge of building safety in Oslo's steep terrain, particularly as urban development expands into historically unstable areas.