Lahar in the Rabacca Dry River, which flows from the mountains of the La Soufrière Volcano, northeastern St. Vincent. (5:07 PM, April 13th, 2021, Hayden Billingly)
|Present La Soufrière Alert Level:||ORANGE||There is a highly elevated level of seismic and/or fumarolic activity or other unusual activity. An eruption may begin with less than twenty-four hours’ notice.|
Professor Richard Robertson, lead scientist from the University of the West Indies Seismic Research Centre (UWI SRC) that is monitoring the La Soufrière Volcano says that the next explosion at La Soufriere can be expected in the next seven days. However, he has warned the public that it would be unwise to re-enter the La Soufrière Volcano Red Zone, even in the quiet periods when there are no explosions taking place. He has emphasized that the volcano has not ceased eruptions as yet.
Professor Robertson said that once a volcano has shown that it can be as dangerously and violently explosive as La Soufriere has, it is in an individuals’ best interest to avoid it at all costs.
The professor also explained on Tuesday that the La Soufrière Volcano is currently in the phase where the most deaths during volcanic eruptions occur. Robertson said that persons should, specifically, stay away from Rabacca, an area with a dry river that offers a commanding view of the volcano, which has been erupting since April 9th.
#Lahar at Rabacca Dry River, St. Vincent as rainfall remobilized #LaSoufriere's hot volcanic ash. Note that NEMO has advised people to stay away from the Rabacca Bridge and those found in the Red Zone will be arrested.— TTWeatherCenter (@TTWeatherCenter) April 12, 2021
Video: SVG TVhttps://t.co/hfrbl6FrQt pic.twitter.com/1bH5L4qk4P
“Rabacca is a bad idea, extremely bad because Rabacca is one of the primary paths for pyroclastic flows to come down,” he said, referring to fast-moving super-hot masses of volcanic material that flow down valleys during an eruption. He said Rabacca is also a primary path for lahars, adding that if these mudflows are big enough, they will not necessarily be confined to the valley, which is under the bridge.
“A proper lahar comes down; it doesn’t need a pyroclastic flow to do that. It will take out all of that and take out the sides, and the Rabacca will re-establish its full extent.” He said that the Rabacca does not begin at the beginning of the road at the bridge. “The Rabacca starts all the way back, about 2 or 200 meters, so it is very wide. When you think you’re standing on the side of the Rabacca, you are actually in the Rabacca. And if you are in the Rabacca, first of all, a mudflow could take you out. And if the mudflow then didn’t do the damage, if it is erupting, it then goes into an explosive eruption, you are caught in a mudflow, a pyroclastic flow could come down, and then that will finish you,” Robertson said.
Drone footage of a #lahar at the Rabacca Dry River bridge.— TTWeatherCenter (@TTWeatherCenter) April 14, 2021
Reminder: If found in #LaSoufriere’s red zone without police permission, even if a resident, you can be arrested.https://t.co/yaSG4ZM7pc pic.twitter.com/SXU9x6E3mv
“The first thing I would say is that the volcano hasn’t stopped erupting yet and that everywhere in the Red Zone is extremely dangerous, even during these lulls because we don’t know how long the lulls are going to be,” Robertson said in his daily update on NBC Radio St. Vincent and the Grenadines.
“The pattern seems to be like that now, but the volcano has shown that it can change its pattern within minutes without any other indication,” he said of the volcano, which last exploded on Sunday, after a 41-hour lull.
“Once volcanoes are erupting as they are now, and once they have shown that they have a potential to be explosive and could be dangerously and violently explosive as this one has shown, it really makes sense for you to stay away from them, even if it looks now like there are periods when there is very little happening.”
Robertson said that the volcano could erupt again within a week, whether or not it succeeds in building a dome, as he said it seems to be trying to do. The professor said that even if it seems that the time between explosions is increasing, “the chances of something happening within a certain time frame, that is, with the current pattern. “The pattern could change before I finish speaking, and suddenly you have a different thing.”
He said there is a certain element that experts know, but there is also a lot happening that they do not quite understand or know. “And, therefore, we give, as best we can, projections as to what will happen and in that regard, it means, therefore, that people need to be very careful, need to be conscious that red is still red; it’s still dangerous,” he said, referring to the Red Zone.
Robertson said that while there is the current period of “apparent quiescence,” where the volcano appears not to be doing much at the surface, there is still a lot of shaking at the volcano. “So it is doing a lot. It (magma) is trying to get out. And we don’t know exactly when it will get out, even though it seems like it has a pattern,” said Robertson, who has said that he believes the volcano has only emitted one-third of the new material it will produce during the current eruption. “So, don’t be fooled. It has been shown from studies that these are the periods when people are most at risk, and the chance of people being killed is highest.
According to the UWI SRC, the volcano continues to erupt. Its pattern of seismic activity over the last few days is typical of the growth and destruction of lava domes. Explosions with accompanying ashfall, similar to or larger, can occur with little or no warning impacting St Vincent and neighboring islands.
The alert level remains red. The National Emergency Operations Center continues to be fully functional operating on a twenty-four-hour, around-the-clock basis. NEMO will continue to provide regular updates as they continue to monitor the Volcano.
Official information will originate from St. Vincent and the Grenadines National Emergency Management Organization and the University of the West Indies Seismic Research Center.