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The Norwegian fjord landscape - beautiful but dangerous
The steep mountains and deep fjords of western Norway can be gorgeous. But in a brief moment beauty can turn into an inferno.
Rock solid?
Although rare, rock avalanches have caused many of the largest accidents associated with natural hazards in Norway. On average there have been two or three major accidents every century.
During the last 100 years, more than 170 people have lost their lives to large rock slides in Western Norway.
Lodalen - 1905 and 1936
The dangerous outcome of these rock avalanches is due to a secondary effect...
...if the rock masses hit a lake or a narrow fjord, it creates a tsunami, with terrible consequences.
Lodalen, Nordfjord 1905:
A huge piece of the mountain Ramnefjell detaches during the night, and falls into the lake. This causes a 40 meter high tsunami.
61 people were killed, 26 of them children.
Lodalen, Nordfjord, 1936:
For the second time, the mountain Ramnefjell terrorizes the inhabitants. Around 04:30 AM a rock mass of 50 000 cubic meters detaches, and creates another tsunami.
74 people were killed, 30 of them children.
01 / 02
1
From one catastrophe...
Loen, Vestland county
2
...to another
Tafjord, Møre og Romsdal county
Tafjord - 1934
This is Tafjord, a small village situated in the innermost part of Storfjorden.
In the middle of the night, on April 7th 1934, the mountain cliff Langhammaren at 730 m.a.s.l. (arrow), suddenly collapses and plunges into the narrow Tafjord.
The 3 000 000 cubic meters of rock cause a huge 60 m high tsunami in the fjord. The waves are 17 meters high when they strike land.
The tsunami reaches the villages of Fjøra, Sylte and Tafjord.
The photo shows Fjøra after the disaster.
At this time there were no roads along the fjords. The boats were destroyed in the tsunami, so the survivors were isolated..
To help with the rescue work, the locals had to go up to the mountain lakes, and bring boats down to the fjord.
The consequences of this event were huge property damage and 40 deaths, 17 in Fjøra and 23 in Tafjord. Photo from the funeral.
Discovery of new threats
Sometimes it is only by coincidence that life-threatening dangers are discovered, like this one:
Åknes, Storfjorden, Møre og Romsdal, 1930s:
Along the Storfjorden there are many small mountain farms, lying in steep, green mountainsides.
The nature is barren, and farm animals have to climb far up in steep terrain to find grazing. To look after the animals, boys and girls also spend time on these mountainsides.
One of these mountain farms, at Ytre Åkerneset, had goats, and one of the boys watching over the goats was Per Åkernes. While running after goats above their farm, they often passed the crack called "remna".
When he was a boy, Per Åknes remembers this crack as just wide enough to put his hands inside, but very deep. The children often threw stones, to hear them fall far down inside the mountain.
Åknes, 1983:
Per Åknes and his brothers are back in the mountains in Storfjorden. By coincidence they find "remna", which has turned into to a frightening sight. The crack is now two meters wide.
At first this threat was overlooked by the authorities. But in 2004, after a formal report of concern from a geologist, a survey was ordered from the Norwegian geological survey (NGU).
In 2006 Åkneset was rated as a high risk object: If the entire unstable mountain part fails (red area in the figure), 54 million cubic meters of rock will topple into the fjord.
Another rockfall scenario, in yellow, is classified as very likely, with an annual probability of 1/100. This constitutes around 18 million cubic meters.
A failure would cause a tsunami which will affect a large area. With the largest rock avalanche scenario, the settlements of Hellesylt and Geiranger will have the largest run-up height with respectively 85 and 70 meters ashore.
This figure shows the run-up height for different locations, for one of the Åknes scenarios. The yellow dot is Åknes.
Based on these severe consequences, daily surveillance was established in 2004/2005.
There are seven unstable mountains with continuous surveillance today in Norway.
Read more about how NVE monitors potential rock avalanches in the Storymap: