The La Soufriere volcano erupted Friday morning on the Caribbean island of St. Vincent, then again in the afternoon, sending columns of ash more than 20,000 feet into the air.
The eruptions followed mandatory evacuation orders from the government. Roughly 16,000 people live in the "red zone" near the volcano and required evacuation, according to Erouscilla Joseph, director of the University of the West Indies' Seismic Research Center.
“More explosions could occur,” she said Friday morning, adding that it was impossible to predict whether any potential upcoming explosions would be bigger or smaller than the first one.
There were no immediate reports of casualties from the eruption that occurred four days short of the 42nd anniversary of the last significant eruption.
Ashfall had already reached the country's airport on the opposite end of the island nation shortly after the first eruption, the country's disaster risk management agency said. Heavy ashfall also was reported in communities around the volcano, Joseph said.
Several flights also were canceled and islands including Barbados, St. Lucia and Grenada prepared for light ashfall as the 4,003-foot volcano continued to rumble into Friday night.
The volcano last erupted in 1979, and a previous eruption in 1902 killed some 1,600 people.
Two Royal Caribbean cruise ships and two Carnival cruise ships arrived Friday at St. Vincent to help transport the thousands of people who evacuated their homes. A third Royal Caribbean ship was scheduled to arrive within the next few days. Islands that have said they would accept evacuees include St. Lucia, Grenada, Barbados and Antigua.
In the coastal town of Barrouallie, about nine miles from the volcano, evacuees trudged toward shelters carrying backpacks, duffel bags and shopping bags stuffed with personal belongings after the explosion. Some prepared to stay there, while others were expected to board the cruise ships or go to nearby islands that have offered help.
Activity increased dramatically at the volcano starting Thursday, Weather.com said. A series of earthquakes were detected at the site, indicating magma rising toward the surface. Gas and steam seeping from the volcano also started increasing, another harbinger of an eruption.
Contributing: The Associated Press
This article originally appeared on USA TODAY: La Soufriere volcano erupts on St. Vincent in the Caribbean