The La Soufriere Volcano continues to cause mayhem and misery in the Caribbean on the island of St. Vincent, where lahars are an additional problem caused by the explosively erupting volcano. According to information received from scientists at the Belmont Volcano Observatory, there were lahar flows within the river system in the central and northern parts of the island this morning, which are also considered “Red” and “Orange” zones of the volcanic-ash-dusted tropical island.
A lahar is an Indonesian term that describes a hot or cold mixture of water and rock fragments that flows down the slopes of a volcano and typically enters a river valley. According to USGS, lahars generally occur on or near stratovolcanoes, such as those of the Aleutian volcanic arc in Alaska and the Cascade Range in the Western U.S.
La Soufriere is a stratovolcano that has a history of producing lahar flows. A moving lahar looks like a boiling slurry of wet concrete, and as it rushes downstream, the size, speed, and amount of material carried can constantly change. The initial flow may be relatively small, but a lahar may grow in volume as it entrains and incorporates anything in its path – rocks, soil, vegetation, and even buildings and bridges.
On St. Vincent, recent heavy rains mixing with copious amounts of volcanic ash are responsible for the lahars.
Because the lahars can pose a danger to persons visiting the Red and Orange Zones on St. Vincent, the Royal St. Vincent and the Grenadines Police Force will be restricting person travelling into the Red and Orange Hazard Zones. According to the forecast received from the St. Vincent and the Grenadines Meteorological Services, occasional showers are expected to continue during the course of the day and from late Wednesday into the end of the week. This rain could add to additional lahar flows. Even where flows aren’t an issue, rain-soaked ash can create extreme visibility concerns as if someone was tossing wet concrete onto one’s windshield.
The National Emergency Management Organization (NEMO) is also urging persons to desist from visiting the Red and Orange Volcano Hazard Zones due to the potential danger.
More than 30 explosive eruptions have occured at La Soufriere since the eruption began in early April. Scientists with the University of West Indies Seismic Research Center (UWI-SRC) say additional explosive eruptions could occur at any moment with little notice; they are keeping conditions at “RED ALERT” there. “People have been asking if it is now safe to return as explosions have paused and the answer is NO”, said the UWI-SRC in a statement. “La Soufriere remains at a red alert level because it is still venting.”