At 2,829 m (9,281 ft), Pico do Fogo ("Peak of Fire") is the highest point in Cape Verde and the archipelago's only active volcano. It is a steep stratovolcanic cone rising from inside a caldera about 9 km wide on the island of Fogo, about 570 km off West Africa. Its most recent eruptions came in 1951, 1995 and from 23 November 2014 to 8 February 2015, when lava buried most of the villages of Chã das Caldeiras on the caldera floor. The volcano, its crater rim and the Monte Velha forests have been protected since 24 February 2003 as Fogo Natural Park, which covers 84.69 km², or 17.8% of the island. Life on the mountain is shaped by two clocks: the eruptions, which come every few decades, and a sharp yearly swing between a cool dry season and a short summer rainy season that decides whether its farmers eat.
The Bordeira, Chã das Caldeiras and the 2,829-Metre Cone
Fogo is essentially one volcano. The island is nearly round, 26.3 km by 23.9 km, with an area of 476 km² and 35,837 people at the 2015 count. Its summit is a vast caldera, roughly 10 km north to south and 7 km east to west, set towards the north-east of the island rather than in the centre. Near-vertical walls about one kilometre high, known as the Bordeira, ring it on the north, west and south, reaching about 2,700 m. The east side is open. About 73,000 years ago the eastern flank slid into the ocean, and the resulting tsunami, dated from boulders it threw onto Santiago, is estimated at 170 m high.
The flat floor of the caldera, Chã das Caldeiras ("plain of the calderas"), lies at roughly 1,625–1,700 m. Out of it rises Pico do Fogo itself, the young cone that grew after the collapse. The main cone erupted in 1680, its summit last erupted in 1769, and since then lava has broken out from fissures on its flanks. Its magma chamber sits roughly 16–24 km down in the ocean crust. Two hamlets, Bangaeira (founded 1917) and Portela (1920), make up the caldera community of around 700 people, the highest village in Cape Verde.
Because the summit is so high, the volcano runs through several climates. The coast has an average temperature of about 23–25 °C. Above roughly 1,000 m the climate is a cool highland steppe, and the highest ground averages only 12–14 °C. São Filipe, the island capital at 20 m on the west coast, receives about 272 mm of rain a year; Chã das Caldeiras, more than 1,600 m higher, receives about 524 mm. That altitude gradient is why the seasons matter so much more here than on Cape Verde's flat islands.
December to May: The Cool, Dry Months on Fogo
Fogo's year splits into two unequal halves. The colder dry season runs from December to May, when north-east trade winds blow and rain is rare. In the caldera this is the coldest stretch of the year: monthly mean temperatures in Chã das Caldeiras sit around 11.5–12.3 °C from January to April, with average lows near 8 °C, and the caldera periodically gets frost in the winter months. It is Cape Verde's coolest village.
For the people of the caldera, the dry season is about stored water. The non-drinking water used by Chã's households is rainwater caught in large cisterns, and those tanks have to last from November until the rains come back in July. Visitors may climb the cone only with a local guide.
On the coast the dry season is hot desert weather. São Filipe has a hot desert climate under the Köppen system, with an average temperature of 24.2 °C, and its black volcanic sand beach at Praia da Bila sits below a town whose 19th-century sobrados were paid for by wine, coffee and jatropha grown on the volcano's slopes.
2–3 April 1995: Fissures Open in the Dry Season
Eruptions on Fogo do not follow the seasons, but the 1995 one shows what a dry-season event looks like. Small earthquakes began about six days beforehand and grew stronger through 2 April; a large one struck at about 8 p.m. Just after midnight, fissures opened on the flank of the cone. One resident said it looked as if the cone had "been cut by a knife".
Strombolian explosions gave way to a curtain of lava fountains, and by 2 a.m. a flow had cut the road to Portela. The 1,300 people then living in the caldera fled overnight to villages on the north coast. On 3 April a dark ash cloud rose 2.5–5 km and settled over the island; on 4 April fountains reached 400 m. Lava bombs up to 4 m across landed as far as 500 m from the vents. About 3,000 people were evacuated in the first days. The lava ran west to the caldera wall and turned north, destroying houses and the main water reservoir. A new spatter cone more than 140 m high grew beside Pico do Fogo. No one was killed, although about 20 people needed medical treatment.
July to November: The Rains on Fogo's North-East Slopes
The warmer wet season starts in July and ends in November. Across Cape Verde, which belongs to the semi-arid Sahel belt, rain falls irregularly between August and October in short, heavy downpours, and most of a year's total arrives in September. Fogo does better than its neighbours. Its high slopes catch moisture from passing clouds, so drought is less severe here than on low islands such as Sal, which records only about 145 mm a year.
The rain is uneven. The north-eastern side of the island, facing the trade winds, gets the most. Around Mosteiros, 24 km north-east of São Filipe, August and September are the wettest months. Coffee was introduced to Fogo in the 18th century, and the Mosteiros plantations lie between 350 and 1,300 m on volcanic soil. Their output reached 500 tonnes in 1900 but has since fallen to just over 100 tonnes a year. Mosteiros celebrates its patron, Nossa Senhora da Ajuda, around 15 August, at the height of the rains.
The same months are the Atlantic hurricane season, and many of the largest storms begin near these islands. Direct hits are rare: since 1851 only two hurricanes have struck Cape Verde, in 1892 and in 2015. That year Hurricane Fred crossed the archipelago on 31 August. Its damage fell mainly on the northern Barlavento islands, and its rain did farmers more good than harm overall.
September in Chã das Caldeiras: Cisterns and Vines
Up in the caldera the rainy season peaks in September, which alone brings about 198 mm of Chã's 524 mm year. It is also the warmest month, at a mean of about 15.6 °C. This is when the cisterns fill and the vines put on their growth. Days in the caldera are usually hot and dry and nights cool and damp, and in a year with enough rain the vineyards, about 1.2 km² in all, produce semi-sweet grapes.
The vines are said to have been introduced by a Frenchman, the Count of Montrond, who stopped on the island in 1870 on his way to Brazil. Chã is now the only part of Cape Verde that grows grapes in quantity and makes export-quality wine. The farmers' cooperative, the Associação dos Agricultores de Chã, sells it under the "Chã" label. In 2006 it pressed 100,000 kg of grapes into 40,000 cases. The caldera's farmers also grow apples, quinces, pomegranates, figs, beans, maize and potatoes, and keep goats for cheese. The caldera and its rim are the island's botanical stronghold too: 31 species are endemic to the island, and 84% of them grow in Chã and on the Bordeira, including the endangered Echium vulcanorum and the critically endangered Erysimum caboverdeanum, both found only on the outer rim.
When the Rains Failed: Fogo's Famines from 1774 to 1943
The flip side of the short wet season is that a single failed one can be catastrophic. Cape Verde has suffered droughts and famines since at least 1747. A famine that began in 1774 hit Fogo and Brava hard; across the islands about 20,000 people starved, and Fogo's population fell from about 5,700 to 4,200 by around 1777. Deaths from starvation were common again on Fogo in the 1830s.
The worst came in the 1940s. In the famines of 1941–43 and 1947–48, an estimated 45,000 Cape Verdeans died. Estimates of Fogo's own losses range from 31% of the island's population in 1941–43 to half of it, depending on the source and the years counted. Portuguese colonial authorities forbade reporting the deaths, and no food aid was sent during the Second World War. Emigration followed again and again. After the 1680 eruption, ash ruined Fogo's fields and many islanders fled to neighbouring Brava and the other islands of Cape Verde, and many households today live on money sent home from Fogo families in Massachusetts, Rhode Island and Europe.
23 November 2014: Lava at the Turn of the Seasons
The latest eruption began as the rains ended. After several days of heightened seismic activity, strong earthquakes started at 8 p.m. on Saturday 22 November 2014, and the caldera's roughly 1,000 residents spent the night outdoors. Shortly after 10 a.m. on Sunday 23 November, the eruption began and evacuation got under way. The Cape Verdean volcanologist Bruno Faria said its intensity exceeded 1995 and approached 1951, one of the strongest eruptions recorded on the island.
The flows crept across the caldera floor through the dry season. Portela's houses were overrun, and by the time activity stopped on 8 February 2015, after 77 days, about 75% of the buildings in Portela, Bangaeira and Ilhéu de Losna had been destroyed, most of them buried. No one was killed. Most residents left afterwards. Cabeça Fundão, on the edge of the park, became the seat of the natural park, and by 2017 houses and small hotels were being rebuilt. Since 2014 the peak and its caldera have appeared on Cape Verde's 200-escudo banknote.
The people of Chã know the rhythm well: eruptions every few decades, and cisterns that must be refilled every September. For how Fogo's cone compares with other mountains that grew inside collapsed summits, see our guide to the largest calderas in the world, and for planning a trip around the seasons described here, read the best time to visit Cape Verde.