Something was happening up there in the mountain area to the west of the Tjelle settlement. Farming people at Tjelle, certainly also on Trollmyr and Rød, knew that above the wooded hillside just west of Tjelle, there had been changes in the landscape.
By Geologist Christer Hoel, M.Sc.
Read more: Rock Avalanches in the Fjords
This does not seem to have been talked about in the settlements, but the people who walked in the mountains to Tjellasetra, could not fail to notice a crack which clearly every year became wider and deeper. They did not interpret this feature, nor the fact that during the last autumn and spring there were increasingly frequent rockfalls in the mountain Tjellafjellet.
The Rock Avalanche west of Tjelle
Chaplain Kristian Morsing, who later wrote about the accident, along with the others on the rectory nonetheless noted with some unease that it seemed that there would be an increase to severe weather this Sunday, the 22nd of February 1756. There had been heavy raining during the last two weeks and now the wind began to blow from the southwest, just the wind direction which was hardest in the fjord. Towards the evening the wind increased.
Just before the pendulum clock was about to turn its eight strokes, something happened which Morsing suddenly noticed. Suddenly a violent shaking in the ground occurred together with a strong rumbling from the west. At first he thought it was a thunderstorm, but the terrible noise continued. Walls, floors, furniture, everything was shaking as if the whole house was about to collapse.
A rock avalanche was happening between the settlements of Tjelle and Gramsgrø without making direct damage other than on mountain pasture buildings on top of the avalanche area, but the rock mass hit the fjord with such speed and with such huge volume that tsunamis were developed that devastated everything in its path. Three large tsunamis moved outward and inward the fjord. All farms and locations near the seaside came into waves which were up to 40-50 meters high. Livestock, buildings, boathouses and boats were crushed and disappeared in the winter darkness, and through the noise sounded everywhere screams from people and animals. The air was filled with stone dust and a strong sulfur fume.
Tsunamis devastated the shoreline in Langfjorden and Eresfjord
Three tsunamis after another devastated the shoreline in Langfjorden and Eresfjord, branches of the Romsdalsfjord, and far ahead. The waves reached 200 meters up on the shore in some places. As far out as Veøy, 25 kilometre from the rock avalanche area, waves went 20 meters beyond the normal flooding. Here too they caused material damage. Likewise, on Gjermundnes 40 kilometres away, it was reported about destruction. Several days went before it was possible to comprehend the extent of the damage, for the fjord was long in rebellion and made it difficult to cross by boat. 32 people lost their lives in the accident. In all, 168 buildings were destroyed, as well as 196 large and small boats. Large amounts of forest, roads and landing places for boats disappeared, as well as the Fagerpine, a particularly large tree that was a well-known landmark.
All beaches were washed free from soil so they appeared almost white, debris was laying everywhere and in the mountain side around 1 km to the west of Tjelle there was a huge, gaping sulfur vaporing wound. The scientists believe that at least 12, maybe 15 million cubic meters of rock had moved down from 400 meters height. In the mountain slope the stones were pulverized into a kind of ball bearing, giving the mass an astonishing high speed into the sea. With a fjord which is relatively narrow and with a depth of approximately 300 meters where the rock avalanche happened, enormous waves were created.
The mountain side to the west of Tjelle has a slope of 20-30 degrees and appears as a not very likely place for avalanches to occur. But some characteristic and fatal features it is still easy to find. The bedrock is is a layered rock with splits parallel to the fjord, and people had for many years noted a growing crack in the rock. Furthermore, behind was situated a marshy area which gave constant water inflow. The accident came after a wet autumn had been followed by a mild and unusually wet February, with report on storm flood in Surna exactly the same day as the rock avalanche happened. The extreme rainfall may have been a contributing factor.
The Tjelle rock avalanche is the largest rock avalanche recorded in Norway in historic time. Tjellafjellet has since then remained stable.
Blå Sko – Song about Tjellefonna
This article is written by Geologist Christer Hoel, M.Sc. – Linkedin
- http://gunnarhustad.blogspot.com/search/label/Langfjorden (Photo: Gunnar Hustad)