KINGSTOWN, St. Vincent and the Grenadines — A volcano in the southern Caribbean that had been dormant for decades erupted in a billowing blast of gray smoke Friday, spewing clouds of ash for miles and forcing thousands to evacuate.
The volcano, known as La Soufrière, on the northern tip of the main island of St. Vincent, in St. Vincent and the Grenadines, had started showing signs of renewed activity in late December.
It moved into an “explosive state” on Friday morning, the National Emergency Management Organization said in a Twitter posting.
The emergency management agency said that the ash fall had been registered as far as the country’s international airport on the southern part of the island — more than 12 miles away — while an ash plume had billowed 20,000 feet over the Atlantic Ocean.
The morning eruption was followed about six hours later by a “second explosive eruption” that was not as extensive, the agency said.
Video clips shot in Chateaubelair, a town on the foothills of the volcano, showed the sky darkened by ash as people wearing face masks trudged through the streets lugging their belongings. Other clips posted on social media showed homes and streets blanketed in grayish white ash.
There were no immediate reports of casualties from the eruptions, and the extent of any damage in the surrounding area was unclear.
The eruptions came a day after officials had raised the alert level following several small tremors detected at the volcano, with clouds of steam seen erupting from its peak. The country’s prime minister, Ralph Gonsalves, ordered a full evacuation of the area.
“All arrangements have now kick-started and the process begins,” Mr. Gonsalves said at a news conference on Thursday.
“I want to urge all our people to be calm — do not panic,” the prime minister said. “With God’s grace we will get through this very well.”
As of Friday morning, close to 20,000 people had been evacuated from the area surrounding the volcano, according to officials.
The coronavirus may complicate evacuation efforts, however, according to Erouscilla Joseph, director of the University of the West Indies’ Seismic Research Center.
“The Covid pandemic is still ongoing and you’re talking about moving people for what may be weeks, possibly months,” Ms. Joseph said in a phone interview. “This is a huge cost in terms of a humanitarian effort.”
Prime Minister Gonsalves said on Thursday that in order to board the cruise ships sent to evacuate people from the island, evacuees must be vaccinated, while the nearby island nations that are planning to accept refugees will also require vaccinations.
Islands that have said they would accept evacuees include Antigua, St. Lucia, Grenada and Dominica.
“Amazing on this dangerous road to Jericho we have the good Samaritans,” Mr. Gonsalves said at a news conference on Friday. “It brings home that we are one Caribbean family.”
On Thursday, Mr. Gonsalves had recommended that those who arrive in shelters on St. Vincent be vaccinated as well. He said they were trying to reduce the risk of infecting older people and those with disabilities by putting them in guesthouses, rather than in shelters, when possible.
“We don’t want to have an outbreak of Covid in the shelters,” he said.
Scientists warned that eruptions could continue over days and even weeks.
“Once it has started its possible you could have more explosions,” said Richard Robertson, a professor of geology at the University of the West Indies, during Friday’s news conference. “The first bang is not necessarily the biggest bang this volcano will give.”
Some of the most destructive volcanic eruptions on record are part of the history of the Caribbean’s mountainous islands. In 1995, the Soufrière Hills volcano on Montserrat, a British territory, roared back to life after more than three centuries of dormancy. Over the next two years it would bury half the 39-square-mile island in ash and rock, including the capital, Plymouth, and render much of Montserrat uninhabitable.
Grenville Draper, a geologist at Florida International University, called it “the last really long-lived eruption” in the region.
In St. Vincent and the Grenadines, the population of 95,000 people on the main island had been on edge for months in fear of an eruption of their volcano.
Some still vividly recalled La Soufrière’s last eruption, in 1979, which hurled debris thousands of feet but caused no fatalities thanks to a hastily arranged evacuation of residents to local beaches. Its ash reached as far as Barbados, 100 miles east. An earlier eruption, in 1902, killed nearly 1,700 people.
Cecilia Jewett, 72, a roads supervisor with the government of Saint Vincent and the Grenadines, said she suffered through the 1979 eruption and recalled the scenes of panic and the desperate scramble for water, the sky darkened by ash and the overpowering stench of sulfur. Her father, she said, survived the deadly 1902 event and told stories of victims buried in ash, and corpses lying in the streets.
“Those stories come back to my mind on hearing that the La Soufrière was acting up,” she recalled when interviewed last December. “It’s just too much. These young people would not understand. They think it’s just an explosion.”
“The sulfur, what it does to your eyes, your breathing, your very existence,” she continued. “It was a time I would not want to relive.”
St. Vincent and the Grenadines has a population of 110,000 spread across three dozen islands. Most people live around the capital, Kingstown, on the southwestern coast of St. Vincent island.
Ernesto Cooke reported from Kingstown, and Oscar Lopez from Mexico City.