A volcano in Iceland erupted for the fourth time since December on Saturday, the country’s meteorological office said, spewing smoke and bright orange lava into the air in sharp contrast against the dark night sky.

In a video shot from a Coast Guard helicopter and shown on public broadcaster RUV, fountains of molten rock soared from a long fissure in the ground, and lava spread rapidly to each side.

The eruption began at 8:23 p.m. local time and the fissure was estimated to be about 2.9 kilometres long, roughly the same size as the last eruption in February, the Icelandic Meteorological Office said in a statement.

Authorities had warned for weeks that an eruption was imminent on the Reykjanes peninsula, just south of Iceland’s capital, Reykjavik.

The site of the eruption was between Hagafell and Stora-Skogfell, the same area as the previous outbreak on Feb. 8, the Met Office said.

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“This was definitely expected,” said Rikke Pedersen, head of the Nordic Volcanological Centre.

“Of course the exact time of the eruption is impossible to predict. The first cues of this moving towards the surface actually only happened about 15 minutes in advance,” she said.

The website for Reykjavik’s Keflavik Airport showed it remained open both for departures and arrivals.

Lava appeared to be flowing rapidly south toward the nearby fishing town of Grindavik, where a few of the nearly 4,000 residents had returned following earlier outbreaks, the Met Office said.

The town was again being evacuated, public broadcaster RUV reported. An outbreak in January burned to the ground several of its homes.

“We’re just like, this is business as usual,” Kristin Maria Birgisdottir, who was evacuated from Grindavik in November, told Reuters.

“My son… just called me and said, ‘Mamma, did you know the eruption has started?’ And I was like, ‘Yeah, I did know.’

“So it’s like we don’t even bother telling each other anymore.”

Icelandic police said they had declared a state of emergency for the area and the Civil Defence authority dispatched a helicopter to survey the extent of the eruption.

The nearby Blue Lagoon luxury geothermal spa immediately shut its doors, as it did during previous eruptions.

Iceland boasts more than 30 active volcanoes, making the small, nordic island a prime destination for volcano tourism — a niche segment that attracts thousands of thrill seekers.

In 2010, ash clouds from eruptions at the Eyafjallajokull volcano in the south of Iceland spread over large parts of Europe, grounding some 100,000 flights and forcing hundreds of Icelanders to evacuate their homes.

Volcanic outbreaks in the Reykjanes peninsula are so-called fissure eruptions, which do not usually cause large explosions or significant dispersal of ash into the stratosphere.

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Gases from the eruption were traveling westwards out at sea, the meteorological office said.

Scientists fear the eruptions could continue for decades, and Icelandic authorities have started building dykes to divert burning lava flows away from homes and critical infrastructure.

The February eruption cut off district heating to more than 20,000 people as lava flows destroyed roads and pipelines.

Iceland’s seismic and volcanic activity is due to its location between the Eurasian and the North American tectonic plates, among the largest on the planet, which move in opposite directions.