I’ve blogged about this volcano before. It can be terrifying when it goes off, and because of the lahar threat, it is deadly all year round.

It went off on December 4 more intensively than usual. The video scenes that apparently were shot at night are showing the incredible darkness under an ash cloud.

Some shots of the eruption online look like the apocalypse, too, and reportedly (Indonesian) there are 41 injuries and 1 death.

Still, the pyroclastic flows reportedly ran out less than 1 km and, frankly, I’m encouraged by videos where people are watching one come down an old lahar track.

Indonesians are among the most volcano-savvy people in the world, and I hope that sight means that this is “just” a slightly larger than usual Semeru eruption and not something along the lines of Merapi 2010.

December 4, 2021, 9:25 p.m., Pacific: This is bad. CNN reports 13 dead thus far, and 98 injured. They haven’t been able to get to some villages yet. A volcanologist I follow tweeted (Spanish) that it appeared to be vulcanian (one-shot, basically) and VEI 3.

December 5, 2021, 9:54 a.m.: Per this source, quoting officials, heavy rains triggered a partial dome collapse. And the death toll is slowly rising as they work their way farther into the affected area — a dangerous task because it is still raining and the rest of rhe dome could go at any moment.

Dome collapses don’t show many precursors, as I understand it.

Featured image: National Disaster Mitigation Agency via the Jakarta Post.