The Turrialba Volcano, around 30 miles east of Costa Rica’s capital San Jose, has been increasingly active in recent years, spewing ash on occasion, as well as minor eruptions in recent years. 

But on Thursday, the volcano saw its strongest eruption in decades, as the mountain sent ash nearly two miles in the air. Volcanologists captured spectacular video of the eruption, taken by an infrared camera, that shows lava shooting from the volcano’s mouth. 

“It was a single explosion but a really strong one. This means that there was high pressure inside the volcano,” Javier Pacheco, a government volcanologist, told the Tico Times.

An airport nearby was briefly closed, according to the paper, to give staff time to clean runways, which had become encrusted in ash. 

As of Friday, the air around the volcano was still filled with ash and smoke. (You can see a live shot of the volcano here.)

Nearly 11,000 feet, the volcano was a destination for hikers until 2014, when the country closed it off to visitors, due to increased volcanic activity. It’s the second highest volcano in Costa Rica, behind Irazú, an 11,260-foot volcano which last blew its top in 1994.