Gunung (Mt) Slamet is the 2nd highest Volcano in Java. It has a huge base of forested and farm lands and stands alone with no other high peaks nearby. Consequently Slamet makes it's own weather. It is quite a long hike in no matter which route one chooses and a camp is reccommended before going on to the top. The summit of Slamet is on the old crater wall to the east and the sctive fumerole is over to the west.
The summit area is very exposed and prone to very strong winds at any time. By strong I mean difficult to stand up. Slamet is quite dangerous and many unprepared trekkers have perished on her slopes. There are only two routes to the summit in common use today and if coming from the summit in cloudy conditions and you miss the point where the track starts you have a big problem. Getting lost up high in the bush on Slamet is not an attractive situation because the bush is dense and it is a long way to anywhere. Ravines every few meters make lateral travel nigh impossible. Don't push your luck. Very few water sources at altitude.
Take plenty of water.
We climbed again in November of 2006 towards the end of the wet season and the water source at camp 5 was dry. Lucky we had enough to carry on.
In the past there were 3 routes up Slamet but the long route from the resrt town of Batu raden to the south has been closed by park officials as being too dangerous. This is a longish route and I think many groups were getting lost or unprepared for the trip and the officials were getting tired of repeated rescues on this route. It may still be possible using forestry guides from Batu Raden but I have not heard of people using tis route recently.
The most common route is from Bambangan which is quite tricky to get to. Best way is to stay in Purokerto and arrange a guide and transport from there. There is a forestry post there and you may be asked to record details and leave a few rupiahs. If you set off up this trail tou can reach the bushline camping area called Samarantau in 5-7 hours. The trail is posted by tons (literally) of plastic rubish discarded by previous groups. More rubbish here than on any other trail in Indonesia. There are no side tracks and the trail is eroded quite badly. There is water available in the gully below the campsite and your guide porter will be able to fill up a few empty bottles to cook up for the evening meal. there are camp sites spread over a couple of hundred yards from the bush to just out of the bush. I prefer the higher campsites so we have some views, but if weather bad there is more protection lower down. Both times we climbed Slamet it rained. In the morning it is about an hour and a bit to the summit over open hard rock. This trail leads girectly to the summit and from there one can view the crater area and the active fumerole still 1km away to the west. Because of the hard rock there is no formed trail so finding your way back to the campsite could be difficult in the clouds. Take a compass bearing just in case. Usually it will be clear in the morning.
It is quite easy to reach the summit explore a bit and return to Purwokerto the same day.
The other trail leaves from Guci which is quite easy to get to from Tegal railway station using fixed price taxi. Guci is is a small resort set in the northern slopes of Gunung Slamet. There are quite a few little hotels and some hot springs. A nice spot to chill out for a while at an altitude of about 1200m. Find a guide and follow him up the new pleasant trail to the crater rim quite close to the active fumerole. Takes about 4-5 hours to the bushline and an hour or so on up to the rim. Last part is quite steep on shifting scoria. A joy to run down on but frustarting to ascend. To reach the summit one needs to descend into the crater and walk a couple of km around the the east. The wind up here can be diabolical and we turned back at the rim. An interesting trip would be to climb via Bambangan and descend to Guci and the hot springs and massage ladies. The fit could do this in a day with a guide as long as he knows the Guci route down. I think we will do this next time with a camp. ! You would certainly have seen a fair bit of Slamet this way. No water at all on the Guci route.
Twice this year (2006) we climbed Slamet from Bambangan side after staying in the cheap hotels at the bat caves just off the main Pemalang - Purbaingga road. Charter a bemo to the trail head at Bambangan. the second time we camped out on the summit ridge and what a night...the wind did not let up..It battered us all night collapsing several tents that weren't quite up to snuff. camping at the summit allowed us to explore around the crater area but probably better avoided due to the high winds. We arrived in fine weather and the wind rose steadily from dusk and just kept getting worse! Wind chill was way below zero. Next morning we headed down and accross the crater to the Guci path and this was also quite a challenge negotiating the thin razorback trail around the crater and dodging the clouds of sulphur that periodically swept over us. Only thing to do was crouch down and hold ones breath till the wind died down a bit and keep going. The trial from the crater lip down to guci gets steep and rocky just before the treeline and easy to get lost in a whiteout as no marks. The hotwater and beer at guci was a welcome relief to everybody. Will upload pics when I get home
Your guide will handle any forestry regulations re climbing Slamet. It is best to register and pay the small fee.
When To Climb
Best from April to October but Slamet's weather is fickle even by Indonesian standards. Bring hat, gloves and good windproof gear. Good boots make a big difference on the descent.
Conditions usualy clear in the morning and cloud up after 0900.
Did I mention the winds? They will literally blow you away.
Camping is reccommended. No huts. Limited water sources. Best sites just under the bush line on both routes. We camped at the summit last time and got a severe beating from the wind which did not seem to want us there. Even down a bit lower towards the crater was bad. Do not camp in the crater on the flat inviting sand due to the chance of being overcome by fumes. Slamet's activity needs to be seen to be believed..it is impressive and dangerous.
If you can read indonesian there are several websites with info on Slamet and a google search will bring them up.
Smithsonian has up to date volcanic info. Slamet will be declared off limits if there is an increase in volcanic activity or impending signs of an eruption.
Remember eruptions can happen at any time with or without warning so always keep an escape route in mind and be prepared to high tail it off the mountain should anything look amis.
In my untrained opinion activity is centered on the western flanks and the Guci route woiuld be more at risk from an emission that from Bambangan. Watching a video of the recent Bromo eruption, if you were in the crater I don't think you would have much time to worry before the clouds got you in any case!