Norwegian mountain could break in half, creating 80m high tsunami

In the future, a mountainside in Norway will fall into the sea below and create a massive tsunami, but despite the danger, residents near the fjord remain calm.

Mount Akerneset is breaking into pieces. Photo: National Geographic

Akerneset Mountain in western Norway, covered in moss and shrubs, has been slowly crumbling to pieces for decades. The eastern side of the mountain is losing 10cm a year and is gradually sliding into the Sunnylvsfjorden fjord below, according to AFP . "The whole slope is very loose and moving, which could cause a major collapse," said geologist Lars Harald Blikra, standing next to the fissure he has been monitoring for 20 years at the Norwegian Energy and Water Resources Authority. "Falls of rock, broken off from the large mountain, will fall straight into the fjord, causing a huge tsunami. It could happen in two to three years or in 50 years. We don't know."

According to a 2016 risk assessment by the Norwegian Civil Protection Agency, 54 million cubic metres of rock could rupture, creating a tsunami tens of metres high in just minutes, sweeping through 10 fjord villages. In 1934, a landslide just a few kilometres away triggered a dangerous tsunami as high as 64 metres, killing 40 people.

Located in the innermost corner of the fjord, the villages of Hellesylt and Geiranger are most at risk. In the worst case, these tourist hotspots could be submerged under waves of 70 to 80 metres. Olav Arne Merok, a 70-year-old resident who has lived in Geiranger all his life, would be among those affected. “Here we live at an altitude of 30 to 40 metres. Obviously, if there were a 90-metre wave, we would be underwater. But we cannot live in constant fear of that,” Merok explained.

At the marina, where many yachts dock in the summer, Geir Gjorva, a 69-year-old boat agent, also appeared calm. "Nobody knows how big the wave will be. It can come slowly or quickly. It's not something we talk about every day. People know that the warning system and emergency measures work well," Gjorva said.

Because of the danger, Akerneset is one of the most closely monitored mountains in the world. A series of GPS and topographical devices on the ground, along with underground sensors, measure every movement of the mountain, and sound the alarm if necessary. According to geologists, the mountainside will not fall straight into the sea without warning. There will be plenty of signs before a major rupture, giving enough time to evacuate the area.

“Evacuating thousands of people from a small area due to the risk of landslides is a mayor’s nightmare,” admits Einar Arve Nordang, the newly elected mayor of Stranda, the province that includes the villages of Hellesylt and Geiranger. “But we are ready.” Emergency plans are in place, and each agency knows what to do in the event of a disaster.

On Akerneset, experts are looking for ways to delay the disaster. One possibility is to drain the mountain of water, which acts as both a lubricant and a pressurizer. But that would be complicated and expensive, as all the equipment would need to be transported by helicopter. Sverre Magnus Havig, director of the Energy and Water Resources Department, said such an operation could significantly delay the collapse. “Instead of a landslide happening in a hundred years or two hundred years, it could happen in 1,000 years,” Havig said.