Kumbolo

Kumbolo, commonly referred to as Ranu Kumbolo, is a high-altitude freshwater lake in East Java, Indonesia. It lies on the southern slopes of Mount Semeru, the highest volcano in Java, within Bromo Tengger Semeru National Park. The lake sits at an elevation of about 2,400 meters above sea level and is a well-known waypoint for climbers ascending Semeru.

Geography and setting: The lake is in a volcanic basin surrounded by pine forest and grassy meadows. The water is cool and clear, often reflecting the surrounding peaks on calm days. The area experiences a mountain climate with occasional fog and sudden weather changes, particularly during the wet season.

Hydrology and ecology: Ranu Kumbolo is fed by rainfall and springs. The shore supports alpine flora and a variety of birds and insects typical of Java’s highlands. The surrounding zone is part of a protected landscape with active conservation measures.

Access and tourism: The lake is a popular camping and trekking stop on Semeru routes. The usual approaches begin from trailheads at Ranupani or Cemoro Lawang and pass through forested slopes to Ranu Kumbolo, where many trekkers spend the night before continuing toward higher camps and the crater rim.

Conservation and regulations: As part of Bromo Tengger Semeru National Park, the area is protected and visitors are expected to follow park rules, minimize waste, adhere to camping guidelines, and respect seasonal restrictions to protect the lake’s water quality and ecosystem.