The weather can be extreme and unpredictable, the terrain challenging, the altitude can affect your ability to cope, and it’s easy to become lost. And sometimes volcanoes erupt unexpectedly. Be prepared for the worst even in the dry season. Being lost on a mountain at night during a rain storm can be life threatening.
Every year many people die on mountains in Indonesia, most often from hypothermia. The all-too-frequent scenario is: lost on the descent; cold and panicky; continuing to bash down the mountain and getting further lost in the process; inadequate rain protection and warm garments to survive a night in a rain storm; and, insufficient food and water. Remember: ca. 3,000 ms, temperatures can drop to near zero before dawn.
Other causes of injury/death are falls into ravines and craters, usually from not exercising sufficient caution. Concentrate on where you place your feet when trekking. Forest fires on the upper slopes of mountains during extreme dry conditions can be life-threatening. Listen to the advice of your leader/guides and, most importantly, use lots of common sense.
These main causes of injury/death are completely avoidable: adequate fitness, proper survival gear, sufficient food and water, lots of common sense, and attention to advice of team leader and guides. If you ignore these basic rules, you not only endanger yourself but others who may attempt to rescue you.