One plane, a British Airways aircraft carrying 248 passengers and 15 crew traveling from Kuala Lumpur, Malaysia, to Perth, Australia, on 24 June 1982, accidentally entered the ash cloud at night, about 150 km (93 mi; 81 nmi) downwind of the volcano.

[5] Three weeks later, on 14 July, a Singapore Airlines airplane with approximately 230 passengers aboard also inadvertently entered the cloud at night, and three of its four engines stopped.

Houses were built on the hummocks since they provided good defence against hostile people, and being above the paddy fields were free of mosquitoes and rats.

Originally, it was thought that either it had been formed by a lahar caused by the release of the waters of the crater lake, or that it was man-made, composed of rocks and boulders dumped there after being cleared from paddy fields.

Like these mountains, Galunggung has a horseshoe-shaped crater indicating a massive landslide, and examination of shattered lava blocks revealed them to be similar to deposits on the other two volcanoes.