2018 was an eruptive year in Indonesia, with numerous earthquakes felt, particularly on Lombok and in central Sulawesi (Palu region). Indonesia made headlines, unfortunately due to the thousands of casualties who suffered the wrath of Mother Nature.

At the time of writing this article, no fewer than 19 volcanoes were in heightened activity and closely monitored by local scientific authorities. Among them, three warrant particular attention, as they are highly sought after by experienced hikers and trekkers.

Mount Merapi in Yogyakarta

Since August, viscous lava – in an effusive eruption – has created a lava dome at the summit of Mount Merapi that continues to grow at a rate of 3,000 m³ per day. Scientists fear a collapse of this dome, which would result in the release of pyroclastic flows and lava. This is why the local population living near this "mountain of fire" is not permitted to approach the volcano within 3 km. The lava dome remains stable for now, and the alert level remains set at Waspada ("alert" in Indonesian, meaning level II on a scale reaching up to IV). Volcanologists actually estimate that pyroclastic flows could be triggered if the magma flow reached a volume of 600,000 m³ per day. It is therefore advised against climbing Mount Merapi at present (the current rainy season is not conducive to a safe trek anyway), but let us hope that as the next tourist season begins in early May, the volcano will have subsided and many hikers will have the joy of scaling it again. Failing that, they will always have the option of tackling the extinct volcano Merbabu, which faces it and offers spectacular panoramas.

Mount Agung in Bali

After more than 50 years of slumber – its last eruption dating back to 1963 – Mount Agung awoke in 2017 and especially disrupted air traffic, occasionally causing some panic among travelers. Since then, the volcano nicknamed "the summit of the Gods" has calmed, and its last eruption dates to July 25, 2018 (just before the series of earthquakes that shook Lombok). The alert level remains at III (out of IV), and it is therefore inadvisable, for the time being, to approach the volcano within 4 km of the crater.

Mount Rinjani in Lombok

The celebrated Mount Rinjani experienced the consequences of the earthquakes that affected the island of Lombok last August. Numerous landslides blocked access to the caldera, and the national park authorities therefore decided to ban climbing the volcano. Since the end of summer, however, reconnaissance missions have been undertaken to verify access routes, and only the path leading to the hot springs (located near Lake Segara Anak) has been reopened. However, it does not permit continuing to the summit. The traditional routes via Senaru and Sembalun Lawang therefore remain closed to the public, but local authorities have planned to send workers to clear these access points at the end of the current rainy season, around March/April next year. The local people have of course understood that volcanic tourism is an important financial resource for the populations living on the periphery of Mount Rinjani, and it is safe to say that the region will welcome many hikers again from May 2019 onward, for not only does the Rinjani national park offer breathtaking landscapes, but it also allows trekkers to pit themselves against the mountain: climbing Mt Rinjani is challenging (it is no less than Indonesia's second-highest volcano at 3,727 m, behind the 3,805 m Kerinci in Sumatra) and only the most motivated, through considerable physical and mental effort, reach its summit.