Unstoppable rivers of molten rock flowed towards the sea after a new vent in the Cumbre Vieja volcano blew open on La Palma on Tuesday, closing in on a densely populated area of the Spanish island.

The rivers of lava, up to six meters (nearly 20 feet) high, rolled down hillsides, burning and crushing everything in their path, as they gradually closed in on the island’s more densely populated coast.

La Palma experienced several small earthquakes after the vent opened up, two days after Cumbre Vieja erupted on Sunday.

Authorities warn of more dangers that lie ahead for residents, including more earthquakes and toxic gases when the lava meets the ocean.

One lava flow is bearing down on Todoque, where more than 1,000 people live, and where emergency services were preparing evacuations.

So far, the eruption has destroyed about 190 houses and forced the evacuation of 6,000 people.

The lava’s advance has slowed to about 120 metres (400 feet) an hour, according to the head of the Canary Island Volcanic Emergency Plan, Miguel Ángel Morcuende, and is not expected to reach the Atlantic Ocean before Wednesday.

When the lava, whose temperature exceeds 1,000 degrees Celsius (more than 1,800 F), meets the body of water, toxic gases will be produced and explosions could also happen. Authorities have closed off an area of two nautical miles offshore to prevent any possible onlookers from being harmed.

A change in the wind direction blew the ashes from the volcano across a vast area on the western side of the island, with the black particles blanketing everything. Volcanic ash is an irritant for the eyes and lungs.

The volcano has also been spewing out 8,000 to 10,500 tonnes of sulfur dioxide a day, the Volcanology Institute said.

Scientists say the lava flows could last for weeks or months.

The island of 85,000 people is part of the Canary Islands archipelago, a key tourist destination for Europeans.