Why the Faroe Islands are one lava plateau in eighteen pieces

How a lava plateau became the Faroe Islands

About 60 million years ago the North Atlantic began to open, and the lava that poured out along the rift built the ground that is now the Faroe Islands while it was still joined to Greenland. What it left is a succession of mostly basaltic lava about six kilometres thick, part of the North Atlantic Igneous Province of the Paleogene, resting on roughly 30 kilometres of old continental crust that nobody has yet identified. Every island in the group is a fragment of that one pile, cut apart by fjords and sounds.

The pile is layered, and the layers set the shape of the hills. Flows of hard basalt alternate with thin beds of volcanic ash, called tuff, and the two weather at very different speeds. The tuff wears away quickly, the basalt above it loses its footing and breaks off, and the slope steps back to form a terrace. Repeated down a hillside, the process gives Faroese mountains their staircase profile: grass on each tread, bare rock on each riser.

Eruption came in phases. Quiet fissure eruptions alternated with explosive episodes, and in the long pauses between them swamp forest grew on the cooled lava. Thin seams of coal, mainly on Suðuroy, are the remains of those forests. Geologists divide the plateau into basalt series by age for that reason, and each series weathers into a different kind of country.

The lowest and oldest series is thick lava, exposed on southern Suðuroy, on Mykines, on Tindhólmur and along the western side of Vágar. It is often pillared into long angular columns, and on northern Mykines the columns stand vertical and regular to a height of 30 metres. The middle series is built of thin flows with porous layers between them. It crumbles easily, it weathers fastest on the heights, and the debris it sheds fills the low ground below, which produces the smooth curved slopes seen on Vágar, at the northern end of Streymoy and in north-western Eysturoy.

Encyclopaedia Britannica describes the outcome as volcanic rock under a thin layer of moraine or peat soil. In its account the islands are high and rugged, with flat summits separated by narrow ravines. The flat summits are the tops of individual lava flows. The ravines are where water and ice found the weaker beds.

Why the Faroese coast is nearly all cliff

The record gives the Faroe Islands 1,399 square kilometres, the figure the Danish Meteorological Institute and Britannica also use. Wikipedia's geography article splits it into 1,393 square kilometres of land and 7.19 square kilometres of water in the ten largest lakes, which is the same ground counted in two parts. Around it runs 1,117 kilometres of coastline. The group extends 113 kilometres from north to south and 75 kilometres from east to west, from Enniberg at 62°29′ N to Sumbiarsteinur at 61°21′ N and from Gáadrangur at 7°40′ W to Stapin at 6°21′ W.

Most of that coastline is cliff. The islands rise steeply straight out of the sea, the coasts are deeply indented with fjords, and sea stacks stand off many headlands. Many of the islands are long and narrow.

Britannica notes that the narrow passages between the islands are agitated by strong tidal currents, and the Danish Meteorological Institute adds that the currents between the islands are strong enough to cause problems for shipping. Offshore, a branch of the cold East Iceland Current flows round the whole group clockwise. Where it meets warmer Atlantic water, sea temperatures to the north differ markedly from those to the south and south-west, and the mixing produces local variations around every coast.

Of the 779 islands and skerries counted, 18 count as major islands, and Britannica counts 17 inhabited islands. Lítla Dímun is the one significant island without people. The territorial sea extends 3 nautical miles from the coast, and the continental shelf and exclusive economic zone claims extend to 200 nautical miles or to agreed boundaries and median lines.

The nearest land is British. Denmark lies 990 kilometres away.

What the ice did to the northern islands

The islands carry the marks of repeated glaciation above and below the waterline, and the northern group carries them most clearly. On Kunoy, Kalsoy and Borðoy an ice mass moving east and another moving west cut into the plateau from both sides until the mountain range between them was reduced to a narrow ridge. The plateau surfaces there have been worn into rows of narrow ridges running zigzag along the length of each island.

The same northern islands keep the greatest heights. Eysturoy, Viðoy and Kunoy all carry summits above 820 metres. Slættaratindur in northern Eysturoy stands at 880 metres in the record and at 882 metres in Britannica, and Wikipedia prints both figures on the same page; the Danish Meteorological Institute describes the highest ground in the northern islands as reaching nearly 890 metres. Gráfelli, also on Eysturoy, rises to 856 metres, Villingadalsfjall on Viðoy to 841 metres, and Kúvingafjall and Teigafjall on Kunoy to 830 and 825 metres.

The mountains also set the climate around them. The Danish Meteorological Institute records that the northern part of the islands, where the highest and most massive mountains stand, receives more than 3,000 millimetres of precipitation a year, and that it almost always has a prolonged spell of snow or frost in winter. On the highest peaks, summer snowfall is by no means rare.

What the ice left behind is thin. Moraine and peat lie in a shallow skin over the basalt, and the islands have small lakes and rivers but no major ones.

Why Faroese weather changes between neighbouring fjords

The islands sit close to the North Atlantic cyclone tracks and inside the reach of the Gulf Stream, and the Danish Meteorological Institute summarises the result as humid, unsettled and windy, with mild winters and cool summers. The mountains then break that general climate into many local ones. Visit Faroe Islands, the official tourist board, notes that sun, rain, wind and cloud vary from island to island and even from one side of a hill to the other, so that a driver can enter a tunnel in thick fog and come out in sunshine.

What the Tórshavn normals record

The Danish Meteorological Institute published climatological standard normals for Tórshavn in December 2021, covering 1991 to 2020. Over that period the annual mean temperature was 7.0 °C, with monthly means of about 4 °C in January and February and about 11 °C in July and August. Frost fell on 40.5 days in an average year of the period. The annual mean wind speed was 6.6 metres a second, and annual precipitation averaged 1,399.2 millimetres, falling on 264.3 days.

Sunshine is scarce. From 2007 to 2020 Tórshavn averaged 1,002.1 hours of bright sunshine a year, and in December 1942 it recorded none at all. From 2008 to 2020 the town averaged 179.2 days a year with more than 80% cloud cover and 4.0 days with less than 20%. Average relative humidity from 2010 to 2020 was 83.6%, highest in July and August because humid air cooled over cold sea produces frequent fog in summer.

The extremes are wider than the means suggest. The highest temperature measured anywhere in the islands was 26.3 °C at Vága Floghavn on 17 July 2003, and the lowest was −12.3 °C at Kirkja on 4 March 2001. Tórshavn recorded its strongest ten-minute wind of the normal period, 37.2 metres a second, on 25 December 2016, and a ten-minute average of 50 metres a second with gusts of almost 70 has been measured at the Mykines lighthouse on the western edge of the group. Atmospheric pressure can fall by more than 80 hectopascals in 24 hours. Hurricane Faith reached the islands on 5 September 1966 with sustained winds above 160 kilometres an hour, and only then ceased to be a tropical system. Winter records began in 1891, and the warmest winter on them was 2016 to 2017, at an average of 6.1 °C.

How the rain follows the mountains

Air arriving from the west and south-west is lifted by the islands and drops its water, so nearly all coastal areas receive around 1,000 millimetres a year while the central parts of the hilliest islands receive more than 3,000, and investigations cited by the Danish Meteorological Institute found places receiving more than 4,000. The southern and western coasts are the driest. On 15 and 16 September 1998 Hvalvík recorded 182 millimetres in a single fall.

Frost follows altitude and exposure in the same way. Wikipedia's station summaries, drawn from Danish Meteorological Institute records, give the following averages for frost days a year, with the height of each station, since several of them stand well above the villages they are named after.

The Tórshavn line shows why the period matters. The Danish Meteorological Institute's own 1991 to 2020 normal is 40.5 frost days, and the figure of 49 carries no stated period at all. Vágar, where the airport stands on higher ground, combines low temperatures with heavy precipitation and is the one place where measurable snow cover lies with any regularity; in some sheltered coastal spots several years pass with no snow. Occasionally some fjords freeze over with a thin skin of ice.

What grows on thin soil in constant wind

The islands belong to the Faroe Islands boreal grasslands ecoregion. Most of the lowland is grassland, some of it heath dominated by heather, and the rest of the natural cover is arctic-alpine plants with moss and lichen. Britannica describes the vegetation as moss, grass and mountain bog, and the 2012 land-use figures in Wikipedia's geography article put arable land at 2.14% of the total and permanent crops at zero. The main crop is grass for sheep.

Whether the islands are naturally treeless is disputed between the sources. Britannica says they are, because the summers are cool and gales frequent, with some hardy trees planted in sheltered places. Wikipedia records that shrubby willows, junipers and stunted birches colonised the islands after the Ice Age and later disappeared, apparently because of grazing, possibly helped by a turn to wetter and cooler conditions around the same time. Both accounts agree on the present: trees grow where they have been planted. The planted species that have done well come mostly from the Magellanic subpolar forests of Chile, where summers are also cold and the wind blows almost continuously, among them Drimys winteri and three species of southern beech; the black cottonwood, also called the California poplar, has been introduced as well.

There are no native land mammals, and no toads or reptiles either. Mountain hare, brown rat and house mouse all came with people, the brown rat in three separate introductions according to DNA studies. Birds are dominated by seabirds and by species of open heather ground, and several have developed Faroese subspecies, the common eider, the starling, the wren and the black guillemot among them. The pied raven, a colour form found only here, is extinct. Grey seals are common on shores away from settlement, orcas visit regularly, and long-finned pilot whales live in the surrounding water.

How the islands are being joined under the sea

Settlements were long connected by ferry, and the terrain made roads hard to build even within a single island. The first road tunnel opened in 1963. By 2018, according to a study cited in the Island Studies Journal, the islands had 20 road tunnels totalling 44 kilometres, nearly one metre of road tunnel per inhabitant.

Four of them run under the sea. The Vága tunnel opened in 2003 and the Norðoya tunnel in 2006. The Eysturoy tunnel opened in 2020 and cut the road distance between Tórshavn and the village of Strendur from 55 kilometres to 17. The Sandoy tunnel opened in 2023 and joined Sandoy to the road network on Streymoy. Bridges and causeways already linked the four largest islands and three islands in the north-east, so each subsea bore extends one network across one more sound.

The same 2018 study projected that the network would reach 88% of the population once the Sandoy tunnel was finished, and 99% once a tunnel reaches Suðuroy. Suðuroy is the only major island with no fixed link. The national development plan aims to connect the remotest areas by road by 2030, and the island's separateness already shows in speech: Wikipedia's article on the language notes that the southern variety of Faroese is very distinct, possibly because of distance compounded by the lack of a tunnel.

The smaller islands remain outside the network. Koltur and Stóra Dímun have no ferry at all and are served by helicopter. Mykines, Kalsoy, Svínoy, Fugloy, Hestur and Nólsoy have smaller ferries, some with helicopter service as well. There are no railways, and Vágar has the only airport. Visit Faroe Islands notes that turbulence at the airport is well known, and the Danish Meteorological Institute attributes such turbulence to the hills channelling and breaking the wind.

Researchers writing in the Island Studies Journal in 2023 found that local people surveyed about the Eysturoy tunnel valued the shorter journeys and the safety in winter weather, and regarded the toll as too high. The Eysturoy and Sandoy link was financed with debt that the 2018 study put at 55% of the country's total borrowing. As each new road merges islands, the ferry routes across the sound it replaces close.

Where people live on ground this steep

The record gives the population as 54,149 on 1 January 2023, and the Nordic Council of Ministers gives 54,561 for 2025. It lives in 29 municipalities and some 120 settlements. The six traditional sýslur, Norðoyar, Eysturoy, Streymoy, Vágar, Sandoy and Suðuroy, have no legal standing now but are still used to name regions, and each once held its own spring assembly, part of the story Faroe Islands: history tells.

Tórshavn, on Streymoy, had 14,038 inhabitants on 1 January 2024 by the record's count, while the Nordic Council of Ministers gives 23,239 for 2025 in the area covered by Tórshavn municipality. The World Bank series in the record puts the urban share of the population at 39.6% in 2025. The rest of the population lives in villages and small towns, and people surveyed about the Eysturoy tunnel named shorter commutes among its main benefits.

Some of those villages are very small. Saksun had 13 inhabitants when University of Copenhagen researchers wrote about it in 2025, and it and Gásadalur are among the most photographed places in the islands. In 2023 visitors trampling the grass the sheep need led residents of Saksun to post signs regulating where people could walk. On ground where arable land is about 2% of the total, grazing is the main use of almost everything that is not rock.

What the fjords and the rain are used for

A 2026 report for the Falkland Islands Government on salmon regulation found active salmon farming in almost all Faroese fjords, under around 40 licences. Each fjord is managed as a zone that needs its own environmental permit. The whole zone is stocked and emptied as one unit, and the operators use current models to site new pens and track how sea lice spread with the water. Some operators have experimented with breakwaters to protect their pens.

Rain and wind supply much of the electricity, and the islands generate it on their own. The electricity system has no connection to any other country, and some islands still run their own separate systems. In 2014 the islands had six hydroelectric plants and four diesel plants, alongside wind farms working at a capacity factor above 40%, and of the 305.4 gigawatt-hours produced that year hydropower supplied 39.5% and wind 11.3%. A 12 megawatt wind farm near Tórshavn that began operating in 2014 raised installed wind capacity from 6.6 to 18.6 megawatts. The stated goal is 100% green electricity by 2030, and planners have considered converting the existing hydropower to pumped storage.