Within its huge 50 km² caldera sits the crater lake Segara Anak (Child of the Sea). Eruptions within the caldera have formed a new small cone called appropriately enough, Gunung Baru (New Mountain). Segara Anak has a natural hot spring.
The mountain and its satellites form the Mount Rinjani National Park (Taman Nasional Gunung Rinjani) - officially 41,000 hectares within the park boundaries and a further 66,000 hectares of protected forest outside.
In 2008, the Indonesian government proposed to UNESCO that Mount Rinjani be one of the world's official geoparks. If this was approved by UNESCO, Mount Rinjani would become the first such geological park in Indonesia.
This is a very active volcano.
The oldest recorded historical eruption was in 1847. Previous to that this was a very remote region indeed, hence the lack of records.
There was a spate of activity from 1994 to 1995 which resulted in the further growth of the crater cone Gunung Baru, since renamed Gunung Barujari (Finger Mountain).
On 27 April 2009 Gunung Barujari became active again with that activity continuing through to May 2009. The summit ascent routes were closed at that time as the eruptions intensified with plumes of smoke and ash as high as 8,000 m. A Volcanic Explosivity Index (VEI):2 rating was issued for the activity between May and December 2009. The ascent routes re-opened on September 14th 2009 but hiking routes down into the crater lake were still deemed unsafe and remained closed.
In February 2010 observers at the Gunung Rinjani Observation Post detected a smoke plume that rose 100 m from the volcano. The activity in early 2010 is centred about Gunung Barujari. On May 1st 2010 a column of smoke was again observed rising from Rinjani issuing eruptions 1,300-1,600 metres tall with thick brown color and strong pressure. On May 5th 2010 a possible ash plume rose to an altitude of 5.5 km (18,000 ft) and drifted 150 km NW. Accordingly the Center of Volcanology and Geological Hazard Mitigation advised that intermittent activity could produce ash plumes to 1,500 m (5,000 ft) above the caldera. In light of this The Volcanic Explosivity Index Alert Level was raised to 2 with a recommendation that there be no activity within a radius of 4 km from the eruption at Gunung Barujari.
Rinjani erupted three further times on 23 May 2010 with activity continuing until 24 May 2010. According to the volcano's official monitoring agency, ash from Mount Barujari was reported as rising up to 2 km into the atmosphere and damaged crops. Lava flowed into the caldera lake, pushing its temperature up from 21°C to 35°C, while smoke spread 12 km. The volcano did not directly threaten villagers during any of the eruptive activity in early 2010 however access to some sections of the Mountain was officially closed or restricted at some times.
The lower and mid levels of the mountain are quite heavily forested. Above the tree line though the slopes are barren and rugged scree slopes and volcanic rock. The views of the crater lake are quite breath-taking from the caldera rim, as is the sunrise. From the absolute peak you can see Bali to the west and Sumbawa to the east.
Flora and fauna
The lower and middle elevation slopes are densely forested with typical tropical species, including species which occupy the Wallacea transitional region between the SE Asian and Australasian flora. Fig trees are especially apparent in the lower forests, as are the giant Syzigium Jambu, with the gnarled and epiphyte-hung Engelhardia Bak Bakan becoming prominent in the higher elevations. Casuarina woodland (cemara) takes over higher up and eventually these give way to an alpine flora above the treeline.
Lombok is East of the Wallace Line and some bird species with Australasian affinities are therefore apparent. These include honeyeaters, cockatoos and green hanging parrots, in addition to species whose heartland is to the West including tits, weavers and tailor-birds. Bird life can be difficult to observe here due to the density of the forest, though if you have patience and are practised at mimicry many species can be tempted out from cover - if you have the time to spare and the forebearance of your trekking partners.
The familiar long-tailed grey macaque (the Bali temple monkey) is common right up to the crater rim. Of much more interest is the rare ebony leaf monkey which inhabits these forests and whose soft hooting contact call often provides a soothing backdrop to the birdsong. Rusa deer and muntjacs are more often heard than seen.
Rinjani is best climbed during the April-November dry season. The trekking trails are generally closed during the rainy season. In recent years the early months of the 'dry season' have become more prone to rain and you should be prepared to encounter heavy rain and low visibility with slippery tracks underfoot at any time, particularly in the afternoon.
It gets very cold on the mountain above 2,000 m and nears freezing at the summit. Warm clothing is an absolute must.
Most visitors arrive via the village of Senaru (600 m), on the northern side of the mountain and thus closer to the main resort areas of the west coast including Senggigi. The other possible entry point is Sembalun Lawang (1,150 m), on the eastern side, which is closer to the summit.
Both villages are accessed from the main north coast road.
Entry to the park costs Rp 150,000 per person. This fee is split up as follows: 13% to the national park authority, 62% to the Rinjani ecotourism trekking program (which is a shame given that the path are full of detritus thrown away by the guides and porters) and 25% for trek route maintenance etc.
Within the park the only way to get around is to hike. Porters can be arranged to carry your supplies.
Climbing Mount Rinjani
At 3,726 m, Rinjani is the second highest volcano in Indonesia after Sumatra's Gunung Kerinci. It is very climbable by visitors with a high level of physical fitness. Critical is to understand and respect this great mountain: sadly, visitors have died here through failing to follow sensible procedures and make all necessary preparations.
Few actually make the very strenuous effort required to reach the actual summit but instead stop at the crater rim (approx 2,700 m) where the views of the crater lake are mind blowing. To make the extra 1,000 m ascent to the very top requires a considerably higher level of fitness, not to mention strength of spirit and sense of adventure.
Typically, a trek to the crater rim involves two days and one night on the mountain. The longer ascent to the summit can be done with just one night's camping but is often part of a longer trek of 3-4 days and two or three nights.
The current park entrance fee is Rp 150,000. Of this 13% is allocated to the Gunung Rinjani National Park, 62% to the Rinjani Trek Ecotourism Program and 25% to support the Rinjani Trek operation and maintenance program.
An organised trek is by far the easiest, safest and most popular option but it is also quite possible to make all of your own arrangements and just hire equipment from one of the trekking centres on the mountain. Rinjani Park regulations stipulate the use of a certified guide so the people at the centre at the start of the hike are not happy to let you climb Rinjani without. With a lot of patience and explanations you can sign a paper wich says that you are responsible for yourself and not the organisation. You will still pay the entrance fee, but it is by far the cheapest option to walk by yourself.
The mountains Licensed Guide Association (HPI) issues certification to the Rinjani guides and porters but it should be understood that the certification standards and required training are no where near as rigorous as would be expected in many other countries. Serious accidents including fatalities do occur on Rinjani treks when led by these accredited guides.
Proper sturdy climbing/hiking boots are a plus but not neccesary, but a must is a substantial waterproof, windproof jacket, and a head lamp. If you are going to the top, use of poles (walking sticks) for getting through the scree (loose rock) at the top are also highly recommended. By 2,000 m, you will feel like you are not in the tropics any more as rising wet, hot air loses its temperature and may fall as rain. If inappropriate clothing becomes wet difficulties will set in as air temperatures towards the summit are as low as 4⁰C, often with a significant extra wind chill factor. You must prepare accordingly.
Guides and trekking providers
- As explained above, you are able to go without guide with the neccesary preparation, there is so many people walking you will hardly be by yourself. But for a long trip and people with no experience it will be much easier to arrange a guide and porters who carry your equipment and cook for you. -
At times it seems that everyone in Lombok is a trekking guide for Mount Rinjani, especially on the main tourist strip in Senggigi.
Take most of what you are told with a pinch of salt and you will find the most experienced and reputable guides at the main trekking centres at Senaru and Sembalun Lawang. It does happen that tourists who are highly experienced hikers or climbers may find themselves far better prepared and skilled for mountain conditions than the local guides. Codes of conduct have been developed for the local trekking support community that include climbing safety, environmental awareness and responsible use. Some of the guides and trekking organisations are better than others at respecting these agreements and guidelines. It is also a good idea to independently check for any volcanic alerts that may have been issued for Mount Rinjani.
Many visitors have found it is preferable to avoid package deals purchased away from Senaru, and instead negotiate either with one of the trekking providers listed below or with the guides themselves to ensure that they are actually competent. If there is a problem, you can then find a different guide company in Senaru or Sembalun.
To help you judge the experience, abilities and equipment provision of a potential guide and support team it may assist to consider the following:
Mobile phone reception is good on the entire mountain except within the crater.
Guide fees are generally negotiable. Only the Rp 150,000 park entrance fee is set by the park authority. A sensible package price range would be:
These trekking fees will vary though according to how busy the guides are, how many people are in your party and if a commission is due to a referring person or agency. Some guide companies will charge as little as Rp 900,000 per person for a 2-night trek in the off-season, but it is important to check they are properly experienced, equipped and provisioned. Ensure your trek price is all-inclusive of any extra charges for transportation, provisions, porter fees and the park entrance fees.
For the sake of future generations, please check that your trekking operator adheres to the 'pack it in / pack it out' policy for litter, and ask all your participants to take responsibility for collecting their own litter and carrying it out.
The following all offer organized treks with accommodation, transport to the mountain, return to your accommodation and can also help with hiring a private guide if required:
Serious trekkers should explore the options of staying on the mountain for 3 nights or more with a planned trek that takes in the crater rim, down to the lake shore, the absolute summit and more. Such treks normally start in either Senaru or Sambulan Lawang however in the last couple of years some other routes have opened including the Benang Stokel, Timbanuh and Torean routes.
The Senaru ascent route
This is by far the most used route as it allows the (relatively) less strenuous trek to the crater rim only. You start at an elevation of 600 m in Senaru village, normally in the late morning or early afternoon and make the 6 hour ascent to the crater rim before dark. First part of the trek is through tropical rainforest. Look and listen out for the lutung, or black monkey, swinging through the trees in the late morning. They are extremely shy, unlike for the common macaques which may gather near rest stops waiting for scraps. The route passes through POSII at 1,500 m, breaches the treeline at 2,000 m (POSIII) and then it is a bit of slog up gravel paths to the camp site just below the crater rim at 2,600 m. There is no clear path at the last section nearing crater rim, at an incline of 45 degrees. There is a POS Extra after POS 3, but it is pretty much gone, and the remaining bits have been chopped up by porters as firewood.
If that has not sapped all of your energy you can then make a very precarious descent down to shores of the crater lake and bath in the hot waters. You need some confidence to do this as it is a steep descent of 600+ m using handrails and ropes.
And then it is back to Senaru the way you came. Local guides claim going down is faster, but speed varies for individuals. Patience is vital for first timers, as it can get frustrating watching porters sail past you with their load balanced on one shoulder, clad in slippers or even walking barefoot. Descent from POS Extra to POS 3 can be slippery when weather is dry, as scree tends to give way under your feet. From POS 3 to POS 2, the descent can take 1.5 to 2 hours, as savannah grasslands fades away, and the humidity and heat from the tropical rainforest begins to set in. Useful tip: request for guides to cut out a wooden trekking pole if you did not bring a trekking pole with you. It will be extremely handy during the descent, especially when legs are aching from the strenuous climb.
There is an option to go on to Plawangan II where you overnight again before making the ascent to the absolute summit. This is not especially recommended from the Senaru side though. If you want to get to the top, the climb to Plawangan II is best made from Sambulan Lawang.
The Sembalun Lawang ascent route
Starting in the morning from the Rinjani Trek Centre in the village, the climb to Plawangan II at 2,638 m will take about 8 hr via POSI (1,300 m), POSII (1,500 m) and POSIII (1,800 m). Starting altitude is1100 m, so there are no humid conditions to deal with. First half or more of the trek is literally a breeze. The trek through savannah grassland is windy and easygoing, with gentle ups and downs, and the only obstacle to look out for are the "cow pats" deposited by the villagers' cows along the way. Rolling hills and amazing scenery help to ease the tiredness, unlike the enclosed tropical rainforest of Senaru route. From POS 2 to POS 3, the climb is still manageable. The challenge for Sembalun route is from POS 3 to POS Extra, as the uphill gradient can be 50 degrees at times. Young children will find this section challenging as some steps are set quite far apart. Cooler weather up here may give the impression that the body does not need fluids, but do drink more to prevent altitude sickness setting in. Strangely, there is a guy selling cold drinks (Pocari sweat, Coke etc) here at the campsite at exorbitant prices (40000 Rp per drink) for those who crave it. Overnight at the campsite here and go for the summit starting at 3AM the next day. You need to be well rested as this is a stiff task - the final climb is nearly 1,100 m on difficult ground.
The Benang Stokel route
Departs from the village of Aik Berik in Central Lombok and is is about 27km east of Mataram or a little less than an hour’s drive. Locally Benang Stokel is well-known for its 2 waterfalls, the Benang Kelambu waterfall and Benang Stokel waterfall. Treks normally depart from this waterfall location. The ascent up to the crater rim takes around 6 hours. From there a descent to the crater lake requires a further 3 hours. This track offers lots of variety and includes the Tiara Dewi Anjani waterfall. This is an route suitable for experienced trekkers.
You do not have to climb to the summit of Mount Rinjani to enjoy the splendours of the national park. Indeed unless you really think that you are physically capable it would be foolhardy to even try. You will find plenty of guides in either Senaru or Sembalun Lawang to suggest lower level treks through beautiful valleys.
In and around Sembalun Lawang you will have the opportunity to purchase unique and high quality hand woven cloth.
If you are trekking outside of an organised group, you should carry in all necessary food for your trek. Fresh fruit and high energy foods are especially appropriate. If you are planning to make the ascent to the absolute summit try to carry a special food item with you for celebrating your achievement of reaching the top.
Trekking packages usually include food which is carried and prepared by the porters.
There are simple restaurants at the lodges in Senaru and Sembalun Lawang.
If you are trekking independently, stock up with some liquids at Senaru or Sembalun Lawang. A flask of hot tea or coffee is very appropriate.
There are a lot of fresh springs on both routes and these determine the positioning of the campsites. You therefore do not need to carry large quantities of water with you. The springs can run a little dry sometimes but all guides should know the status of each spring beforehand.
There is no lodging in the park itself, but some simple places to stay can be found at Senaru & Sembalun Lawang.
Pondok Senaru Beach Cottage is a typical guesthouse that offers a variety of Standard, Deluxe and Superior rooms (approximately 10 rooms total). Basic amenities like towels, soap and bottled water are present, but standard rooms have no hot water. There is no air conditioning, not that you will need it, as temperatures drop to below 20 deg Celsius at night. Breakfast included. There is a warung across the street if you need variety.
Tanjung on the nearby northwest coast has several more upmarket offerings, and both it and the Gili Islands are reasonably close to Mount Rinjani. Many visitors choose to stay in the Senggigi region and travel north to Mount Rinjani by road.
Accommodation for the Senaru route
Accommodation for the Sembalun Lawang route
Camping is possible at designated rest shelter areas on the ascent routes, and at the crater rim.
This is a very active volcano. Always be aware of the current assessment of eruptive activity. Sources worth keeping an eye on include local media and The Smithsonian Institute's weekly Volcanic Activity Report . Do not always take the word of a trek organiser as gospel on safety issues.
Rinjani is high enough that altitude sickness is a concern. Be aware of the symptoms and treatment.
It is also very cold up on the summit (4 to 5°C), so warm, windproof clothes are a must as are appropriate hiking boots and a head lamp. The sun can be very strong during the day and severe sunburn is a risk.
Make sure that your guide is carrying a radio with him and that it is fully charged and working. A test call to the trek centre is advisable. The trek centre has a satellite telephone and it can be used by visitors - ask to see the chart of charges.