Gunung Semeru (3,670 m) is the third highest volcano in Indonesia after Kerinci (3,805 m) and Rinjani (3,726 m) and the highest in Java. Semeru is spectacular for its volcanic cone and phreatic, steam/ash, eruptions (about every 20 minutes or so depending on its mood). The vertical ascent from the trailhead at Ranu Pane to the summit is about 1,560 m – quite easy in a three-day hike except for the final ascent which is quite tough.
The final ascent to the summit involves a 600 m climb up loose scree –hard but doable if you take it slowly. You will certainly appreciate the views from the summit especially at sunrise. Being an active volcano, treat it with respect – stay away from the crater rim and be alert for eruptions and ash fall.
Along with Argopura, the trek into the base of Semeru’s volcanic cone is one of the finest in Java. The trail passes through vegetable gardens, sub-montane forest and, at higher altitude, Cemara forests (Casuarina junghuhniana) and tussock fields.
Java Lava normally returns to Surabaya for the flight home via the inside of the Tengger Caldera to Gunung Bromo (2,329 m). This drive is spectacular for the extensive ‘sea of sand’ being ash deposits from Bromo’s occasional eruptions. Gunung Bromo is one of the most famous tourist attractions in East Java. See Gunung Bagging – Bromo for more about Bromo’s mystique, religious significance, sunrise views, and more.
The Semeru trip normally takes four days with two nights camping on the mountain.
Day 1: Early morning flight to Malang; by car and change to 4×4 jeep at Tupang to reach the trailhead at Ranu Pane (2,109 m); leave travel gear at a losmen at Ranu Pane for return; sort guides/porters and packs; trek to Ranu Kumbolo about 10 km or 3-4 hours easy walk along a well-formed trail of easy gradient.
Ranu Kumbolo (2,382 m) is a small lake nestling in the mountains. This is a beautiful camp site but ‘the coldest campsite in Java’ with temperatures to below zero at night. Don’t be surprised if your boots are frozen in the morning if left outside your tent.
Day 2: This is a relatively easy and delightful trek through Cemara forests and tussocky fields until reaching the base of the Semeru volcanic cone. Here, there are two camp sites: the lower, Kali Mati (about 2,700 m), with water from a spring about one km away, is a popular camping area; and, the higher, Arcopodo (2,912 m), about two km and one hour beyond. Ranu Kumbolo to Kali Mati is about five km and takes about three hours.
Day 3: The ascent of the cone is hard going up loose volcanic scoria – ‘two steps up, one step down’. Or, if you are a ‘mountain goat’, you can literately run up the scoria moving on before it slips away under your feet. From Arcopodo, the climb is about 600 m and takes about 3-4 hours for normal humans. Start at 0200 hrs to be at the summit for sunrise. Dawn is very cold on the summit – jackets, balaclavas, gloves!
If you arrive before dawn you can see the glowing cinders in the eruptions. Do not get too close to the crater rim – follow the advice of the guides. If conditions are unsafe due to increased volcanic activity – descend!
The descent to Ranu Pane takes a full day. It’s a long trek so your ‘going down’ muscles need to be in good shape. A more adventurous route from Ranu Kumbolo to Ranu Pane is via Gunung Ajekajek – this route is steeper but shorter and offers excellent views.
Day 4: after recovering at Ranu Pane and taking on ‘Java Lava juice’, the trip continues by 4×4 jeeps through the inside of the Tengger Caldera, across the ‘sea of sands’, to Gunung Bromo and viewpoints on the edge of the caldera, before heading to Surabaya airport for a late evening flight home.
Suitability: the trek into the camp below the summit cone is long but not difficult; reasonable fitness; families with older children. The climb up the summit cone is very strenuous – families should assess whether they wish to subject their children to this final climb. Some kids will ‘romp’ up the slope, others may have problems.