As the name implies, the Sequoia/Kings Canyon Operations Area encompasses the Sequoia and Kings Canyon National Parks in California's Sierra Nevada mountains. The largest cave in the parks is Lilburn Cave with over 20 miles of surveyed passage. Survey and scientific work are carried out both in Lilburn and in numerous other caves in the parks.
The project began in 1980 with the goal of adding more detail to some of the main passages. Since then the 7.8 miles of known cave has been resurveyed using modern sketching techniques and standards and over 14 miles of survey has been added to the known length making it the longest cave in California. For managing the cartography of one of the caves with the highest passage density in the world, the passages are split out into quadrangles both horizontally and vertically, which results in 91 separate maps that are required to better represent the 22.25 miles of surveyed passage of Lilburn Cave.
As an offshoot of the cartography project, there is an ongoing cave inventory project at Lilburn Cave, with the main trade routes being continuously monitored. Research has shown that it can take up to 23 cave inventory surveys in order to fully capture a single location, so this is a long-term project for Lilburn Cave, especially for the more remote sections of the cave.
Caves serve as archives of past weather events, storing in its layers of calcite deposited through millennia the history of the local climate. Picking the right cave with just enough lag between the surface weather and its expression in the chemical composition of the water in the cave is crucial so that regular fluctuations are captured but out of the ordinary events don’t skew the records. The study of the correlation of current local weather outside of the cave with the water chemistry in the cave can help us understand how the weather patterns could have been in the past based on the analysis of the different layers of calcite, effectively giving us a window to the climate in the past.
Started in 1993, work in the Mineral King area involves cave inventory and survey of the area's caves. Access to the area is only possible during a brief window by the end of summer, when the snow in the higher elevations has melted enough to gain access to the terrain and caves, and before the first winter storms bury them back. The challenges of access and working at high elevation are offset by the natural beauty of the area.
Software analysis of lidar scans of the park has allowed the identification of a vast number of karst features of interest, many, many more than previously known. This project focuses on a systematic reconnaissance of promising areas in the park which had been previously overlooked. The exploration potential is immense.
Page last updated December 2025
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