Conditions on the Caribbean island of St. Vincent have worsened, as La Soufrière volcano continues to push ash and debris into the atmosphere. Dozens of individuals have been rescued from the northern part of the island after refusing to evacuate last week. Officials are warning anyone still in the red and orange zones to flee as the mountain presents a new danger to anyone still in the area.
There is evidence of pyroclastic flows, an avalanche of super-heated gas and debris traveling as fast as more than 120 miles per hour along the mountainside, in the areas around the volcano, University of the West Indies Seismic Research Center's lead scientist Richard Robertson said in a Sunday news conference. These flows are the most dangerous trait of the volcano, he said, as opposed to a slow-moving river of lava.
As La Soufrière continues to explosively erupt, ash and debris are launched into the air. Sometimes there isn't enough force behind the materials to continue upwards and the ash plume collapses on itself and it shoots back down, Robertson said. These clouds of gas can reach scalding-hot temperatures and carry car-sized boulders as the flows make their way through valleys along the mountain. Once the pyroclastic flows hit the coast, the sea water begins to boil and the clouds pick up speed, racing across the surface of the water and away from land until they run out of energy.
"These flows are really moving masses of destruction," Robertson said. "They just destroy everything in its path. Even if you have the strongest house in the world, they will just bulldoze it off the ground."
These flows can happen as the volcano goes through periods of explosive activity and venting. Every hour-and-a-half to 3 hours, Robertson explained, La Soufrière rumbles and produces tremors as the mountain vents more ash. This activity can create pyroclastic flows anywhere on the volcano, threatening anyone who didn't evacuate last week.
During the news conference, St. Vincent and the Grenadines Prime Minister Ralph Gonsalves said the coast guard has rescued dozens of people from the northern part of the island since the volcano started to erupt Friday morning. The areas closest to the volcano were ordered to be evacuated last week, but some people decided to stay, putting rescuers at risk.
"I'm pleading with persons, please, it's past the hour to get out," Gonsalves said. "And we will still have to try and get you out."
Some 16,000 people have already evacuated, The Associated Press reported, about 3,200 of whom have fled to 78 government-run shelters.
Robertson said things will likely get worse before they get better. Instruments monitoring the eruption have shown no sign of activity dying down. The volcano, he explained, is showing a similar pattern to the volcano's eruption in 1902 that killed about 1,600 people.
"That means it's probably, unfortunately, going to cause more damage and destruction to St. Vincent," Robertson said.
But the volcano isn't just affecting the people of St. Vincent. The winds have carried ash all the way to Barbados, about 120 miles east. Barbadian Prime Minister Mia Amor Mottley said the country needs to prepare itself for weeks of ashfall and harsh times.
"As bad as it is, it can be worse, and that's the first thing that we need to recognize," she said in a news conference Sunday. "We are living in uncertain times."
Dr. Erouscilla Joseph, director of the UWI Seismic Research Center, said the winds that carry the debris east over the island can then also circle back around, blanketing the island with more ash from the west.
"Unfortunately, the worst case scenario is this can go on for weeks because of the changes and the dynamics of this system," Joseph said. "We have to keep monitoring the seismicity associated with the volcano and advise based on that."