Update 10.04.2021
At the time of writing, there have been several explosive eruptions now from La Soufrière St. Vincent. The island has experienced extensive ashfall. The emergency evacuation has extended to the orange zone. Ash has reached 51,000 feet (38,000 feet, latest VAA) according to the volcanic ash alerts and the ash cloud has drifted over Barbados.
Most of the new lava dome has been destroyed and the 1979 lava dome has suffered some damage. Removal of the rock has given magma a more open pathway. The eruption is expected to be larger than the 1979 eruption and to continue for some time; explosions are expected to be the same or greater magnitude. As far as we know, there have not been any pyroclastic flows but they are expected.
More than 3,000 people are in emergency accommodation and others are staying with friends or relatives. Saint Lucia, Grenada, Antigua and Barbados have offered to take refugees. Carnival Cruise Lines and the Royal Caribbean Group will send cruise ships to transport people to other islands. Venezuela has sent humanitarian aid and risk experts.
The north and west of Barbados have been hard hit by ash; the skies turned dark and ash is falling. Residents have been advised to stay indoors, except for essentials or a medical emergency. Beaches, parks and fish markets are closed for the time being. People with respiratory disorders have been advised to have their medication with them at all time. The airport and airspace is closed at the moment.
Latest VAA forecast:
Thoughts with everyone affected.
Sources:
NEMO St. Vincent: #lasoufriereeruption2021
Hazard zones, St Vincent: Home (nemo.gov.vc)
Washington VAAC: Volcanic Ash Advisory (noaa.gov),
News 784: NEMO: Explosive Eruptions May Continue Over The Next Few Days And Weeks • News784
Barbados Government Information Service: GIS News | GIS (gisbarbados.gov.bb)
Nation News, Barbados: Volcano ash turns northern skies dark – NationNews Barbados — nationnews.com
Update 16:51, 09.04.2021
An explosive eruption started at La Soufrière St. Vincent around 12:40 pm GMT today, sending an ash column 8 km into the sky. The ash cloud reached 20,000 feet, drifting eastwards. Ashfall has been observed at Argyle International Airport.
Scientists warn that further larger eruptions are possible.
The evacuation from the red zone (northern end of the island) is still in progress at the time of writing.
Source: NEMO St. Vincent and the Grenadines | Facebook
Original Post: 12:46, 09.4.2021
Good Afternoon!
Increasing gas emissions and seismic activity, including long period events, indicate that new magma is ascending at La Soufrière St. Vincent and an eruption could be imminent. An immediate evacuation order was given earlier today (c.1:00 am GMT) for the red zone in the north of the island, impacting 16,000 people.
The new lava dome has been steadily growing since it emerged in December 2020. The emission of gas and stream from the centre of the dome and its border with the 1979 dome increased on 8 April 2021. A preliminary VAA noted that a well-defined hotspot was visible in the SW. Incandescence from the dome was visible in St Lucia.
A swarm of volcano-tectonic earthquakes started on 6 April 2021 beneath the volcano at a depth of around 6 km. Long period earthquakes have also been observed, indicating that new magma is ascending.
Background
Volcanic activity, here, is driven by the subduction of the South American Plate under the Caribbean Plate.
La Soufrière St. Vincent is a 1,234m high stratovolcano located in the north of St. Vincent Island, which rides on the Caribbean Plate. She is the youngest volcano on the island. At the summit there is a 1.6 km wide crater with a younger crater formed in the 1812 eruption, located in a 2.2 km wide Somma crater. Her lavas are typical of a subduction zone setting: andesite / basaltic andesite and basalt / picro-basalt.
GVP records 23 Holocene eruptions, the largest of which were VEI 4s in 1812 and 1902. The 1902 eruption devastated much of the northern end of the island. A lava dome was extruded in the eruption of 1971, which was destroyed to be replaced by a new dome in 1979 in a series of explosive eruptions. The 1902 eruption devastated much of the northern end of the island. Pyroclastic flows from eruptions in 1812, 1902, and 1979 reached the coast.
For advice and the status of La Soufrière St. Vincent, please consult NEMO or follow their Face Book page (links below).
Thoughts with those impacted by the evacuation and eruption.
The Armchair Volcanologist
© Copyright remains with the author; all rights reserved, 2021.
Sources and Further Reading
National Emergency Management Organisation (NEMO): Home (nemo.gov.vc) and https://www.facebook.com/nemosvg/
Washington VAAC: Current Volcanic Ash Advisories
The Smithsonian Institution’s Global Volcanism Program (GVP): https://volcano.si.edu/
“Mt. Pelée, La Soufrière St. Vincent and a Quick Tour of the Plates Surrounding the Caribbean”: https://thearmchairvolcanologist.com/2021/02/01/mt-pelee-soufriere-st-vincent-and-a-quick-tour-round-the-plates-surrounding-the-caribbean-plate/
An Armchair Volcanologist 
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