Volcanic debris flow stops in St Vincent…for now

Lahars observed in the Wallibou river (Red Zone, Leeward side of the island) on Thursday morning. Photo by Prof Richard Robertson, UWI-SRC -
Lahars observed in the Wallibou river (Red Zone, Leeward side of the island) on Thursday morning. Photo by Prof Richard Robertson, UWI-SRC -

AS the lahars (flows of volcanic material) come to a halt in St Vincent and the Grenadines, at least for now, the government is assessing the damage they caused, which included landslides and uprooting trees, among other things.

On Thursday, the country experienced heavy rain. With the La Soufriere volcano still active, it was not a good combination.

Heavy rain results in the formation of lahars at a volcano. The UWI Seismic Research Centre defines a lahar as “fast-moving, dense mixture of rocks, ash and vegetation and water…It has the consistency of wet concrete and can cause severe damage to rivers and valleys around the volcano.

"Lahars carry large amounts of volcanic material and may generate a rumbling sound. Where steam can be seen, these are known as hot lahars as the material is meeting still hot/warm deposits.”

Scientists warned about this when the volcano first erupted three weeks ago.

On Thursday, several areas across the country were flooded with water up to six inches deep. At a virtual press conference on Friday morning, the country’s prime minister Dr Ralph Gonsalves said three shelters were also flooded.

People who were evacuated from the northern part of the island (the red zone) are staying at these shelters, hotels or the homes of friends and family.

Gonsalves also said there were nine landslides in total, and a retaining wall at a cemetery had been swept away.

Montgomery Daniel. the country's deputy prime minister and Minister of Transport, Works, Lands and Physical Planning, said there are around 20 “small structures” (houses) near rivers which would have been affected by the lahars.

Gonsalves pointed out that when people are told not to build in these areas, it’s not because he is “trying to keep down the small man,” but rather to help them. He said it does not make sense to build in these areas only for the structures to be destroyed every rainy season.

Seismologist Prof Richard Robertson suggested the government implement a “lahar-ready programme,” similar to its Volcano-Ready Communities Project. He said the more people are educated on the dangers, the less likely they will build in these places.

He also warned those who need to go out to sea to be careful on the west coast, since, “There’s a lot of tree logs (the lahars brought down). They're just sort of floating about the ocean. We went collected some samples and the boatman had to be dodging the logs all the time.

"You can’t speed on the west coast. So, be careful.”


"Volcanic debris flow stops in St Vincent…for now"

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