PORT-OF-SPAIN, Trinidad -- Much of St. Vincent remains covered in ash following eruptions Friday at the island's La Soufriere volcano.
The volcano has been inactive for nearly 42 years.
"There have been three explosive events that occurred during the day," University of the West Indies Seismic Research Center director Dr. Erouscilla Joseph said in a statement on the center's Facebook page.
The ash plume reached as high as 6 miles into the air, with wind taking it as far as 25,000 feet east of St. Vincent, according to official estimates.
Volcano activity continued into the weekend, with Vincentians reporting that rumblings could be heard coming from La Soufriere at night.
"We have had more or less an almost continued period of the venting of many ash up into the atmosphere," Richard Robertson, the UWI Seismic Research Center's lead scientist monitoring the volcano, said Saturday during a national radio address.
On Sunday, the country's national disaster management agency, NEMO, described the day as "dreary" and said everything looked like a "battle zone."
The volcano set off tremors over the weekend, with some lasting as long as 20 minutes, according to the UWI Seismic Research Center.
Explosions and accompanying ashfall are likely to continue over the next few days, the research center said.
Ralph Gonsalves, the prime minister of St. Vincent and the Grenadines, said the government is looking to see if any properties were damaged by the ash. Officials are also trying to figure out how to remove the ash.
Nadia Slater, a spokesperson for the office of the prime minister told ABC News that as of Sunday afternoon 18,000 residents have been evacuated from St. Vincent's red zones. No one has been evacuated off the island yet, according to Slater.
Around 4,000 people have moved into the 72 shelters that have been set up by residents, and three cruise ships will be used as temporary shelters, Slater said.
Power was fully restored Sunday afternoon and the south of the country is still considered to be safe, according to the spokesperson.
Gonsalves announced plans Saturday to mount a cleanup operation, beginning in Kingstown, the capital of St. Vincent, and the Grenadines.
"It's a complicated business, you can't leave it," Gonsalves said. "But, in the disposal of it, you have challenges."
Officials were looking into using street sweepers and water from fire trucks.
Due to low visibility and heavy ashfall, Grantley Adams International Airport will remain closed until noon on Monday, officials said.
The ash has also affected at least one of the island's neighbors.
The government of Barbados is advising residents to use dust masks, wear long protective clothing that helps prevent direct contact with ash and avoid using air conditioning so that indoor air quality is not compromised.
Friday's eruptions came less than 24 hours after Gonsalves gave the order for people living closest to the volcano -- an area declared as the "red zone" -- to evacuate their homes.
Shelters have been set up to house evacuees, while the government has also booked hotel rooms for people to take shelter. Over 3,200 people have opted to use shelters.
Gonsalves said there may be delays in getting food supplies to evacuees in shelters, with numbers constantly changing.
Those impacted by the volcano's eruption are being told to be patient and remain calm, with "additional supplies" coming, according to Gonsalves.
Some countries have also publicly pledged to send supplies or even personnel to aid St. Vincent with recovery efforts. Gonsalves said the United States is among the countries he's been speaking with.
A number of neighboring Caribbean countries have offered to take in evacuees. Several cruise ship companies have also offered to send ships to transport evacuees to other islands.
"Those countries are not going to take you unless you are vaccinated, which is understandable in the time of the pandemic," Gonsalves said.
The last time St. Vincent's La Soufriere volcano erupted was on April 13, 1979.
Dr. Erouscilla Joseph, director of the UWI Seismic Research Centre, told reporters Sunday that previous eruptions lasted six months to a year, and if a "worst-case scenario" were to materialize, it would be in the next few weeks.
ABC News' Ivan Pereira contributed to this report.