On Monday, a sightseeing helicopter in Iceland spotted the Fagradalsfjall volcano’s newest fissure spewing steam and lava, the Associated Press reports.
The Icelandic Department of Emergency Management immediately directed volcano-watching tourists to evacuate the area as scientists evaluated the danger. Local authorities announced on Tuesday that eruption-viewing areas would reopen at 6 a.m. local time on April 7.
The eruption at Fagradalsfjall began on March 19. It marked the volcano’s first eruption in about 6,000 years and southwest Iceland's first eruption in 800 years. Thousands of visitors have trekked out to the two craters to watch the lava flow despite freezing temperatures. (Some scientists even took the opportunity to cook hotdogs on the cooling lava, Michele Debczak reports for Mental Floss.) The eruption has lasted longer than scientists initially expected, and the new fissure gives more evidence that the event is far from over, report Hildur Margrét Jóhannsdóttir and Sunna Valgerdardóttir for the RÚV News Agency.
The volcanic eruption appears to be moving north, says University of Iceland geophysicist Magnus Gudmundsson to the Associated Press. “We now see less lava coming from the two original craters. This could be the beginning of second stage.”
Since mid-March, more than 30,000 tourists have visited the eruption site, which is just 20 miles from Iceland’s capital, Reykyavík. The country usually sees volcanic eruptions every four or five years; in 2014, a fissure opened and oozed lava at Haluhraun, and in 2010, ash from an eruption at Eyjafjallajokull brought international air travel to a halt.
Lava is flowing out of Fagradalsfjall at about 1,500 gallons per second, per RÚV. Volcanoes that spew thin, runny lava tend to be safer to watch than those with thick, viscous lava, which can make it difficult for gas to escape into the atmosphere. In the latter case, an eruption site can become explosive.
“If you know some of the basics, you can observe eruptions fairly safely,” says Jet Propulsion Laboratory volcanologist Rosaly M.C. Lopes to Rachel Ng at National Geographic. “We’re lucky that the most beautiful eruptions—in Hawaii, Iceland, and Stromboli, Italy—are also not the most explosive ones.”
People can often anticipate a volcanic eruption; for example, Iceland experienced weeks of seismic activity in February before Fagradalsfjall erupted. But once an eruption begins, the details can be harder to predict. The new fissure opened without warning, per RÚV. The fissure is about a half-mile north of the original eruption site, and it is about 550 yards long.
Between 400 to 500 people were on their way to the eruption viewing site when the fissure was spotted and the evacuation was ordered. Kristin Jonsdottir, the earthquake hazards coordinator in the Icelandic Meteorological Office, told RUV that the fissure raised concerns that a shift in the lava flow’s direction could surround tourists watching the eruption, Ragnhildur Sigurdardottir writes for Bloomberg. But the new fissure does not pose an immediate threat to people, as it is far from popular hiking trails.