A new fissure eruption opened before dawn on 16 July near the Sundhnúkur crater row on Iceland’s Reykjanes Peninsula, roughly 50 kilometres (30 miles) southwest of Reykjavík. The Icelandic Meteorological Office said magma broke the surface with little warning, creating a 700- to 1,000-metre crack that lengthened to about 2.4 kilometres within hours, sending fountains of lava and ash skyward in what has become the region’s 12th eruption since 2021. Satellite and ground-based measurements indicate lava now blankets roughly 3.2 square kilometres. At one point magma encountered groundwater, triggering a brief but powerful phreatomagmatic blast of steam and ash. Despite the spectacle, officials said the outbreak remains modest in volume and does not threaten critical infrastructure. Authorities nevertheless evacuated around 100 residents from the nearby fishing town of Grindavík and some 200 visitors from the Blue Lagoon geothermal spa. The Civil Protection agency warned of high sulphur-dioxide levels and advised residents of surrounding communities to stay indoors and seal ventilation systems. Air traffic at Keflavík International Airport operated normally throughout the event. By 17 July seismic tremor and lava output had subsided, allowing Grindavík and the Blue Lagoon to reopen. Scientists caution that the peninsula, dormant for eight centuries until 2021, has likely entered a prolonged eruptive cycle that could last for decades, characterised by recurring but relatively small fissure eruptions rather than plume-forming blasts capable of disrupting trans-Atlantic flights.