[28] The eruption began at 14:13 local time (14:13 UTC) on 19 September 2021 in a forested area[23][29] called "Cabeza de Vaca",[26] of Montaña Rajada, in the Las Manchas section of the municipality of El Paso.

[35] On the fourth day, according to the Volcanological Institute of the Canary Islands, the volcano entered a more explosive phase, expelling less volcanic gas.

[39] On the morning of 20 September, the Canarian Ministry of Education ordered the suspension of all classes in the schools of the nearby municipalities of El Paso, Los Llanos de Aridane and Tazacorte.

[23][42][43] In the early afternoon of 21 September, the lava reached the neighborhood of Todoque, in the municipality of Los Llanos de Aridane, with 1,200 inhabitants.

[45] On 24 September, the eruptive activity intensified, with further ash and volcanic material falling greater distances, forcing firefighters to withdraw from the neighbourhood of Todoque.

[46][47] On 25 September, Aena, the operator of the La Palma Airport, suspended all flights due to ash accumulation with cleaning tasks underway.

Meanwhile, the volcano seemed to have entered a more stabilised period after the previous days of more explosive eruptions with a slight fall in seismic activity that took place at deeper depths than before, according to IGN.

The heating of the seawater to a high temperature might produce laze containing emissions of sulfuric, hydrochloric, and hydrofluoric acid into the air.

[53] Earlier on that day, Spain's government classified the island of La Palma as a disaster zone, due to the steadily increasing property and economic damage caused by the eruption, a move that will trigger emergency subsidies and other support measures.

This emitted two streams of lava that cut the important LP2 highway and threatened more of the populated area of Los Llanos de Aridane.

[58] By 8 October, according to the Copernicus Emergency Management Service, the lava flow had affected 497 hectares (1,230 acres) of land and more than 1100 buildings had been destroyed.

[63][64] On 11 October, the northern side of the volcanic crater collapsed creating a new lava flow which threatened another urban district known as La Laguna.

[74] The lava flows have also impacted industrial structures such as cement plants, which have also caused gas clouds and explosions, and have affected flights at Tenerife North–Ciudad de La Laguna Airport.

[65][full citation needed] On 25 October, the intensity of the earth tremors had increased and the lava flows to date had destroyed over 2,000 buildings.

[78][full citation needed] On 26 October, a magnitude 4.8 earthquake under Mazo was also felt in Tenerife, La Gomera and El Hierro.

[80] As of 26 October 2021[update], the lava that has flowed from the volcano (on 26 October estimated to be 215 million cubic metres or 7.6 billion cubic feet) has destroyed or affected over 2,100 buildings, over 66 kilometres (41 mi) of roads and covered an area of over 900 hectares (2,200 acres), with volcanic ash fall covering over 5,500 hectares (14,000 acres) within the limits of the monitored area, according to estimates from visual and radar satellite data by the Copernicus EMS.

[78][full citation needed] This caused the authorities to advise the public to close the windows of their homes and remain indoors.

[84] On 28 November, at 03:00 local time (02:00 UTC), a new fissure opened at the foot of the northeastern flank of the main cone, spewing lava and pyroclastic ash.

[93] Hector Izquierdo Triana, born in La Palma and secretary of state for finance at that time, was appointed to the office.

[96] Prime Minister of Spain Pedro Sánchez went to the archipelago shortly after the eruption to see the situation on La Palma first-hand, the coordination of the system and the protocols activated, postponing a trip to New York to attend the Seventy-sixth session of the United Nations General Assembly.

[97] King Felipe VI called the President of the Canary Islands, Ángel Víctor Torres, on the afternoon of the eruption to inquire about the situation.

[97] The following day during the opening ceremony of the university year in Córdoba, the King sent a message of support to "those who are suffering the evacuation of their homes" and thanked the emergency services for their work.

[99][100] On 19 September, the European Union, on request of Spanish General Directorate for Civil Protection and Emergencies (CENEM), activated the Copernicus Emergency Management Service – Mapping to monitor the eruption[59] and the President of the European Commission Ursula von der Leyen announced via Twitter that "additional support, if necessary," would be made available to the Spanish government.

[101] On 20 September, the Minister of Industry, Trade and Tourism, Reyes Maroto, declared that the eruption on La Palma could be used as a tourist attraction to lure visitors.

[102] Her comments caused widespread criticism, because homes, public buildings and businesses began to be destroyed by the lava flows.

[102] The Bishop of Tenerife, Bernardo Álvarez Afonso, offered Mass on 22 September at the Sanctuary of Nuestra Señora de las Nieves in La Palma, together with the priests of the island, to pray for the end of the eruption.

[110][108][90] A newer proposal is Tajogaite,[111] after the Guanche name for Montaña Rajada ("Cracked Mountain"), the area directly downhill from the eruption site.