Hardangerfjorden, the Hardanger Fjord, runs about 180 kilometres from the Atlantic between the island of Bømlo and the mainland, some 80 kilometres south of Bergen, north-east into the mountains of Vestland county until its innermost arm ends at the town of Odda. It is the second-longest fjord in Norway after the Sognefjord and is usually listed as the fifth-longest in the world, and it is more than 860 metres deep off the village of Norheimsund. Its longest branch, the 38-kilometre Sørfjorden, cuts south between the Folgefonna glaciers and the Hardangervidda plateau; other arms reach towards Eidfjord, Ulvik and Granvin. The fjord is a drowned glacial valley, cut by ice and by meltwater under pressure beneath it and flooded as the ice melted and the land rose after about 8000 BC. To see why it looks the way it does, with bare plateaus above, a deep trench below and orchards on the narrow slopes between, follow its making in order, from the oldest rocks to the youngest landforms.
Precambrian basement and the Caledonian collision, 490–390 million years ago
The foundation of Hardanger is old crystalline rock of Precambrian age, overlain in places by Cambrian to Silurian rocks. Across Scandinavia that ancient basement was planed down into an exceptionally flat erosion surface, the sub-Cambrian peneplain, before the first Cambrian seas flooded it. Near the Hardangervidda the same surface can still be traced today, but lifted at least 1,000 metres above where it formed.
What lifted and buckled it first was the Caledonian orogeny, a mountain-building cycle between roughly 490 and 390 million years ago, when the Iapetus Ocean closed and the continents of Laurentia and Baltica collided. In the Hardanger area, sheets of rock called nappes were thrust over the old peneplain, stacking slices of other rock on top of the basement. The Caledonian mountains that resulted were then worn down over the following hundreds of millions of years. Their legacy in the Hardanger landscape is structural rather than scenic: a grain of faults, fractures and weaker belts in the bedrock. Geologists note that many Scandinavian valleys and slopes are straight because they follow tectonic fractures that erode more easily, which helps explain why the later rivers and glaciers here so often ran in long, straight trenches.
Hardangervidda: a Miocene plain lifted in the Pliocene
The plateau to the east of the fjord records the next chapter. Hardangervidda covers about 6,500 km² at an average height of 1,100 metres and is the largest peneplain in Europe. Its flatness is young by geological standards: it was worn down to a near-level surface at about sea level during the Miocene epoch. Then, in the early Pliocene, the Hardangervidda and the whole of the southern Scandinavian Mountains were raised by more than 1,000 metres. Its highest point today is Sandfloegga at 1,721 metres, and the prominent peak of Hårteigen, 1,690 metres, stands above the moorland like a stump.
That uplift set the stage for the fjord: it left a high plain with a steep western edge, scored by valleys, and the rest of Hardanger's relief is the story of what ice did with those valleys. The western side of Hardangervidda is still the rocky, bare, wetter side, with more than 1,000 millimetres of precipitation a year in places, while the east is flatter and more vegetated. Much of the plateau became Hardangervidda National Park in 1981, at 3,422 km² the largest national park in Norway, and its wild reindeer, some 8,000 animals counted in 2008, still migrate between winter lichen grazing in the east and calving grounds in the west.
Ice streams down the Hardanger trough, 2.75 million to 10,000 years ago
During roughly half of the last 2.75 million years, the Scandinavian Mountains carried mountain-centred ice caps and ice fields, and repeatedly these grew into the Fennoscandian Ice Sheet. The ice did not erode evenly. On the high paleosurfaces, such as the Hardangervidda, it spread slowly and divergently and did comparatively little damage, which is why the plateau survives as a plateau. In the valleys the flow concentrated into fast-moving glaciers and ice streams that ground the floors far below sea level. Glacial reshaping of valleys is strongest on the western side of the mountain chain, where the drowned troughs became Norway's fjords. In Hardanger the work was helped by high-pressure meltwater forcing its way under the ice, which deepened the valley further than ice alone. The result is the basin off Norheimsund, more than 860 metres deep.
At the Last Glacial Maximum, about 20,000 years ago, all of the Scandinavian Mountains lay under the ice sheet, which reached south into Denmark, Germany and Poland. As the margin retreated from about 22,000–17,000 years ago, the ice became concentrated over the mountains of southern Norway and northern Sweden. About 10,000 years ago the link between the southern and northern ice centres broke, and the southern centre disappeared about a thousand years later. Most of the moraine, till and outwash material that mantles the mountains formed during this last glaciation, the Weichselian, and the deglaciation that followed.
Folgefonna and the land rising out of the sea after 8000 BC
As the ice melted, the Scandinavian land mass began to rise from about 8000 BC, and the lower parts of the over-deepened valleys were flooded, creating the fjord as it is today. In the Holocene climatic optimum, between 9,000 and 5,000 years ago, the region was warmer than now and much of Hardangervidda was wooded; pine logs are still found preserved in bogs well above the present treeline.
Not all the ice vanished. On the peninsula between the main fjord and the Sørfjorden lie the three plateau glaciers known together as Folgefonna, covering about 207 km² when measured in 2006. Søndre (southern) Folgefonna, at 167 km², is the third-largest glacier on the Norwegian mainland. The name joins folge, "thin layer of snow", with fonn, "mass of snow". Its outlet glaciers have behaved differently: Blomstølskardbreen at the southern end has changed little since about 1960, while Bondhusbreen and Buarbreen grew during the 1990s and have been retreating since 2000. Folgefonna National Park was established on 14 May 2005.
Meltwater from Buarbreen runs down the river into the lake Sandvinvatnet just south of Odda, and Folgefonna meltwater is bottled at source and sold as Isklar. Since 2001 the 11,150-metre Folgefonna Tunnel has run beneath the ice, linking Eitrheim and Odda on the Sørfjorden with Austrepollen on the Maurangsfjorden and cutting a four-hour journey to ten minutes.
What the trough built: Vøringsfossen, Odda, orchards and the Hardanger Bridge
A deep trench with a high plateau on either side produces hanging valleys, and hanging valleys produce waterfalls. Vøringsfossen, at the top of the Måbødalen valley above Eidfjord, has a total drop of 182 metres and a main drop of 163 metres. In 1821 the astronomer Christopher Hansteen estimated it at about 280 metres by timing stones thrown over the edge; a measurement with a string in 1893 gave the true figure. Tourists followed: a bridle path was built in 1872 for English visitors, and the Fossli Hotel at the top opened in 1891. In 1875 Thomas Cook began weekly cruise departures from London to the Hardangerfjord.
The same falling water became an industry. The Tyssedal hydroelectric station on the Sørfjorden started production in 1906 and from 1918 had an installed capacity of 100 megawatts, with average output of 700 gigawatt-hours a year. Its electricity fed the arc furnaces of the carbide and cyanamide works opened at Odda in 1908, then the largest such plant in the world, which ran until 2003. Odda grew from a tourist stop visited each year from 1891 to 1914 by Kaiser Wilhelm II into an industrial town of 4,750 people (2025), with a dialect that linguists study as a new koiné formed by migrant workers. Even Vøringsfossen is now regulated: a dam on the Bjoreio in the Sysendalen valley takes water for power, with a minimum summer flow required for the falls.
The narrow slopes between the water and the cliffs became a fruit district; the climate, soil and seasonal conditions here are believed to suit apples particularly well. The region produces about 40 per cent of Norway's fruit, including apples, plums, pears, cherries and redcurrants. Apples have been grown here since the 14th century, a tradition traced to English monks who first arrived at Lyse Abbey in 1146, and in 2005 juice from Hardanger apples became Norway's third product with a protected designation of origin. Every village along the Sørfjorden, from Kinsarvik and Lofthus to Tyssedal and Odda, is lined with orchards.
The deep, sheltered water has its own economy: fish farms in the fjord produce more than 40,000 tonnes of salmon and rainbow trout a year, making it one of the four major fish-farming regions in the world. About 70,000 people live in the eleven municipalities around it, across 8,471 km². Crossing the fjord was always the problem, and on 17 August 2013 the Hardanger Bridge opened over the Eidfjorden between Bruravik and Brimnes, replacing a ferry. It is 1,380 metres long with a main span of 1,310 metres, the longest suspension span in Norway, running tunnel to tunnel; its deck height of 55 metres means the largest cruise ships can no longer reach the inner fjord.
Seen from the plateau above, the fjord's geology reads like a cross-section, and the Hardangervidda guide follows that high ground east. To compare the making of Norway's longest fjord, read the Sognefjorden guide, or turn north to the narrower, steeper walls described in the Geirangerfjord guide.