Standing at 3726 metres, Mt Rinjani is an active volcano and the second tallest mountain peak in Indonesia. (The highest, at 3805m, is Mt Kerinci in Sumatera.)
The native Sasak consider Rinjani to be a sacred mountain and to Indonesian Hindus, it is one of the three holy mountains, including Mt Agung in Bali and Mt Bromo in East Java.
Rinjani has erupted around 20 times since record-keeping began in 1847 but lava flows have been minimal and only recorded a handful of times. The last eruption was in 2010.
A crater lake on the way to the summit, known as “Anak Segara” (Child of the Sea – a reference to the lake’s deep blue colour) is all that remains of Rinjani’s older sister, Mt Samalas.
Samalas is estimated to have stood over 4,000 metres above sea level before erupting in 1257.
Eight times as powerful as the 1883 eruption of Mt Krakatoa, it was one of the largest volcanic eruptions of all time, pushing an estimated 40 cubic kilometres of volcanic matter into the atmosphere, and causing disruption to world weather patterns for a number of years as well as contributing to crop failures and famine as far away as northern Europe and Africa.
(If one volcanic eruption can do that don’t tell me that humans pumping carbon into the atmosphere for 200 years can have no effect on climate change!)
Evidence of silica deposits in the soil sub-structure as far afield as Greenland and Antarctica has long indicated the occurence of such a mighty volcanic event ocurring sometime in the mid 13th century but evidence linking the episode to the Samalas eruption was confirmed in 2013, with the discovery of the “Badad Lombok”, an eyewitness account of the eruption written on palm leaves in Old Javanese.
Two small volcanic cones have formed in the lake since the 1257 eruption and most of Rinjani’s volcanic activity over the past 200 years has occurred through these.
A trek to Rinjani’s summit is one of the most popular yet most challenging of all the activities on Lombok.
A trek to the rim of the crater lake can be completed in a day but is a 16hr round trip, typically beginning around midnight. A 2 day/1 night trip will take you to right to the lake’s edge, whereas the summit trek can take 3-4 days, depending on how fit you feel, leaving either from Senaru on the mountain’s northern flank or Sembalun on the eastern side.
Things to know before you go – The best time to travel to Mt Rinjani is July to October. Rinjani National Park is closed from January to March as landslides are prevalent during the wet season. It can be cool at night so be sure to pack some warm clothes and a light jacket in case of rain.
The trek to Mt Rinjani requires a reasonable level of fitness and although you are not specifically required to use a guide, it is highly recommended. Hiring a guide and porter makes a lot of sense when you take into account carrying tents and camping gear, as well as food and cooking equipment
A number of reputable companies offer tours to Mt Rinjani but the price can vary greatly so do your research and maybe don’t book until you get here and have a chance to ask around.