'Orange like the sun': visitors flock to Iceland volcano
While volcanologists say the eruption remains "low intensity" for now, initial estimates indicate that its flow is significantly more powerful than the two previous eruptions in 2021 and 2022 on the Reykjanes peninsula.
"When the wind is coming in this direction, it's not so hot... it's warm like a campfire," said Niall Lynch, a 23-year-old Irish guide AFP met in front of the fresh lava flows next to the small peak of Litli Hrutur.
But on the other side of the fissure, the gas released by the eruption makes the area "unbearably hot".
"It's much too hot to stay there for any extended amount of time. I mean it's like 1,000 degrees Celsius (1,800 degrees Fahrenheit)," he added.
The uninhabited area 30 kilometres southwest of the capital had been dormant for eight centuries but has experienced a resurgence of volcanic activity in the last two years.
The eruptive faults reached a total size of around 900 metres overnight, compared with 200 to 300 metres initially, according to the latest update from the Icelandic Meteorological Office (IMO) Tuesday.
"When you look in the centre of the lava flow, it's a lot brighter than I was expecting it to be," Lynch said.
"I was thinking a lot more like the darker colours of blacks and browns, like the rock when it starts to solidify. But right in the centre it's pure orange like the sun. It's amazing."
"Dangerously high" levels of volcanic gases, particularly sulphur dioxide, will accumulate close to the eruption, warned the IMO, which advised tourists not to visit the area.
Access to the site was closed on Monday evening.
During the six months of the March 2021 eruption, and the three weeks of the August 2022 eruption, hundreds of thousands of visitors came to admire the hypnotic spectacle of lava on the outskirts of Mount Fagradallsfjall and the Meradalir and Geldingadalir valleys.
Unlike explosive eruptions that spew out thousands of tonnes of dust, such as the famous Eyjafjallajokull eruption that paralysed air traffic in Europe in 2010, so-called "effusive" eruptions have little impact, apart from lava flows and locally toxic gas spikes.
Big barbecue
The handful of visitors who managed to reach the site before it was closed describe it as the experience of a lifetime.
From the nearest road, you have to traverse a challenging path, the last three winding kilometres of which are through moss and rocks embedded in the soil.
When the lava finally comes into view, with the tiny Litli Hrutur ("Little Ram" in Icelandic) mountain on the left, the feeling is "indescribable", said Jessica Poteet, a 41-year-old American living in Iceland.
"When you cross the hill for the first time, especially when it's the first day, and you see the fountains of lava and you hear the crackling of the solidified rock, it's just unbelievable," she added.
Gudmundur Hauksson, a 26-year-old Icelandic who was also among the first there, said "it's really nice... to come out and connect with the Earth and nature in this fashion."
The powerful smell of volcanic gases and flowing lava is reminiscent of "a big barbecue", according to some visitors.
The air is also thick with the smoke of burning moss, which ignites under the molten liquid.
Volcanologist Thorvaldur Thordarson of the University of Iceland said "we have no idea" how long the natural spectacle will last.
"It could last for a few days, it could last for a month, it could last for six months like the 2021 eruption or it could even last longer than that."