Mount Merapi sent a huge ash cloud billowing into the sky on Wednesday, January 27.

In a country teeming with volcanoes, one stands alone as Indonesia’s most active. Located in Central Java, not far from the royal city of Yogyakarta, Mount Merapi casts a long shadow over this part of the world’s most heavily and densely populated island, home to over half of Indonesia’s entire 270 million-strong population.

And now, the frequently active (and occasionally deadly) volcano is at it again, living up to its name, Gunung Merapi, or “Fire Mountain.”

On Wednesday, Merapi erupted repeatedly, sending hot ash into the air around three dozen times throughout the day, and pushing a river of lava down the flanks of the 2,910-metre stratovolcano. Indonesian authorities reported that the ash was propelled as far as three kilometres from the peak, and it was Merapi’s biggest lava flow since authorities raised its danger level in November, according to Hanik Humaida, the head of Yogyakarta’s Volcanology and Geological Hazard Mitigation Center.

After a morning rain, the volcanic ashfall was turned into gray mud in several villages, and the thunderous sound of continuing eruptions could be heard some 30 kilometers away.

Though there have been periodic eruptions over the past few years, Mount Merapi’s last major eruption in late 2010 killed 347 people, and forced the evacuation of around 280,000 residents from surrounding areas. The phreatic blast altered the shape of the mountain and subsequent smaller eruptions occurred for several weeks.

Instability leading up to this most recent eruption was detected in November 2020, and the first signs of activity occurred on January 4, 2021.

Mount Merapi is one of the world’s 16 so-called “Decade Volcanoes,” designated as those posing the greatest threats to humans based on volcanic activity and proximity to population centres. The name arises from the project in the 1990s as part of the UN-sponsored “International Decade for Natural Disaster Reduction.”