photo: The Río Uluapan resurgence in Oaxaca, Mexico. Photo by Adam Haydock.

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Beyond the Sump Exploration Team


Sistema Huautla is an approximately 75 kilometres long, 1560 metres deep, cave system located in the Mexican state of Oaxaca. It is currently the deepest cave in the Western Hemisphere and 9th deepest cave in the world. Of the deep caves of the world, Sistema Huautla is also noted for its significant overall length. Exploration in Sistema Huautla has been ongoing for the past 50 years and has been closely associated with the development of modern cave exploration equipment and techniques.

One of the great mysteries of Sistema Huautla is the connection to the active resurgence some 10 kilometres away. The resurgence has been confirmed by dye tracing, resulting in it being the subject of several expeditions. Each of these has increased the known length of the cave and closed the gap to Sistema Huautla's Sump 9, known as the “The Mother of all Sumps”. The connection of the resurgence to the main Huautla system would result in a total cave depth of more than 1750 metres. This would make it one of the top 3 deepest caves in the world, and result in the deepest and most spectacular through trip in the world. The "The Huautla Resurgence Project", now known as “Beyond the SUmp Expeditions”, began in 2016, with the goal simply being a sustained effort of an international team of cavers and cave divers to push towards this connection and link Sistema Huautla with its resurgence in the Santo Domingo Canyon. This page is an effort to bring together information about previous trips with the same goal, organized by Dr. Bill Stone and the U. S. Deep Caving Team, and report on current progress of the Huautla Resurgence Project.

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Derek Bristol in Redball Canyon during the 2015 expedition. Photo by Kasia Biernacka.