Viewing volcanoes in Berastagi, North Sumatra

A small, rather dilapidated and unattractive market town of Berastagi would be entirely avoidable if not for the volcanic activity nearby. As it is, Berastagi is the best base for viewing the highly explosive peak of Sinabung, as well as hiking up other, less dangerous volcanoes. Traditional Karo Batak villages in the vicinity may justify a day of travel as well, and to unwind, there's a natural wonder nearby: an underground hot spring.

Sinabung volcano

Sinabung is one of the most active volcanoes in Indonesia - a country composed of extinct, dormant, and active volcanic cones almost entirely. There's obviously no shortage of tectonic activity in this segment of the so-called Ring of Fire, but Sinabung is special: it doesn't just cough out ash clouds or emit viscous lava flows - when it erupts, it explodes. In 2014-15 a few pyroclastic explosions destroyed pretty much every village within 5 km radius from the vent. It takes time to build up such pressure, so don't expect a nightly fire show of the sort Merapi or Ibu volcanoes provide. If you're a serious lava chaser, wait for signs of increasing seismicity, then make Berastagi your home for a while, and stay alert. There's a tiny chance you may witness a "dirty storm" - a very rare phenomenon when a powerful volcanic eruption creates innumerable lightnings inside the ash column. Its mechanism is still unknown - good shots of a "dirty storm" might even have scientific value. There's also a great chance you will see nothing, especially given Sumatra's unpredictable weather.

Sibayak volcano

Of all the volcanoes near Berastagi, Sibayak is the easiest to reach and climb. The hike isn't technical, and a fit person should be able to reach the summit in an hour. There are some nice solfataras along the way, and a lake in the crater changes colour depending on the season (ostensibly, it looks best during monsoon rains, which is the worst possible time to climb any volcanoes). The main reason for the ascent is the aerial views - walk along the crater rim for the best vantage points. On a clear day, Sinabung is perfectly visible in a distance.

Lingga village

Apparently, a lot of effort has been put into converting one of poorest (and therefore, most authentic) Karo Batak villages in the area into a tourist attraction. Much of that effort was rather misguided, and the effect is ambiguous. The cluster of rumah adat - traditional houses - with high straw roofs and unusual primitive paintings on the walls is interesting, but would perhaps make a better impression without the wannabe guides and souvenir sellers. Lingga is definitely worth visiting is you're in Berastagi, waiting for Sinabung to explode or stopping over on your way to Toba Lake, but probably wouldn't justify a special trip. A better idea might be to rent a motorbike and survey the nearby valleys for similar villages as yet free from tourist "development".

Ergendang cave

A sight unknown even to many locals, Ergendang cave is rather unique: a cave sheltering a thermal spring, its main cavern filled with natural hot water. The location is in the middle of nowhere, the access road is horrible, but none of this has prevented people from building a cement soaking pool. For seekers of unspoiled nature, alas, it is now of secondary value; for those wishing to float in a subterranean hot spring, it's one of the very few such opportunities in the world. 

Practicalities

Don't expect luxury in Berastagi. Even comfort here is mediocre. Your choice is between basic hotels along the main road, equally basic homestays on the outskirts, many with farmland views, and the occasional crossbreed of those two types. For transport, public minivans shuttle between villages, and buses connect Berastagi with a few other spots in North Sumatra, including Medan. Sibayak volcano can be visited on foot from the town, for Sinabung, commute to Kabanjahe first. Warning: approaching Sinabung from this side puts you in the path of pyroclastic clouds. If the activity is high, do not come close; view the eruptions from a high point near Kabanjahe instead. To visit Lingga village, renting a motorbike is desirable; for Ergendang cave, it's unavoidable.