Beyond the Sump

Sump 1 in the Huautla Resurgence. Photo by SJ Alive Bennett. 

The Beyond the Sump team previously explored the Huautla Resurgence in 2016 and 2017. The major goal of these expeditions was to push upstream towards Sump 9, known as the Mother of all Sumps, in the Sistema Huautla. If this connection could be made, the result would be the deepest and most spectacular cave through-trip on the planet.

In 2016 we started this project successfully, and found some amazing dry passage - the Passage of the Cheeky Monkey. Soon after though, we were stopped at the most-upstream end of the cave by wall of dark limestone, a flow stone curtain hanging off it, and what looked like the entire amount of water coming out of the resurgence coming out of one little hole, the Squirty Hole. In 2017, we tried to find a dry way past the Squirty Hole, but did not succeed. Nevertheless, we found some of the most amazingly decorated dry cave we have seen in Mexico. Now, the only remaining leads we knew off were two sumps which were offset from the Passage of the Cheeky Monkey.

First we relined both Sump 1 and 2 since our lines never survive a rain season. Our first exploration goal was then to try and find the upstream continuation in Sump 2, since the Passage of the Cheeky Monkey only seemed to be flowing when the cave is in flood. Not far after the deepest part of the dive in Sump 2, the underwater cave opens up into a huge confusing chamber, which Jason Mallinson first found in 2001, and from where a much smaller passage, found in 2016, leads to the dry cave. After several hours searching in this chamber, Zeb and Steve did eventually find some holes which had a large amount of water flowing out of them, but all of these holes were small, and would have potentially ripped a drysuit if pushed too hard. We therefore gave up exploration in Sump 2 at that point, and instead focused on the two remaining sumps in the Passage of the Cheeky Monkey.

Surprise Sump is the further downstream of the two sumps. It started big, then surfaced again, and after a short part of dry cave submerged again. This sump only went for a short distance as well, and sadly just reconnected into the cave in the second sump on our list of remaining leads. This latter sump also had a junction, and following this Zeb pushed the line until the cave became too small. Given the end of this sump (at least the end of what humans fit through), and the small holes in the massive chamber in Sump 2, we now believe that this is the active route of the water in dry season, given the similarities of these passages.

The only small remaining possibility to push further upstream was to penetrate the Squirty Hole. Since Steve is weirdly attracted to tight cave, he went for it, and pushed against the strong flow coming though this small hole. After several attempts, entertaining Andreas and Zeb who were watching this spectacle, he managed to get into a small air bell beyond, but the continuation became even smaller, too small even for Steve to continue. In the meantime, both Andreas and Zeb searched multiple rock piles in the vicinity of the Squirty Hole, which looked like a large amount of water would come out of them in the rainy season, but the hole in between the rocks just became smaller the further they went.

This was sadly the end of our exploration in the Huautla Resurgence. A wall of hard and dark limestone, which did not want to dissolve easily. Maybe a few more thousand of years of flooding, and this hole would become large enough to continue. At least we ticked of all possible leads, and we think we now understand where the water flows both in the dry and rainy season. Now it is time to turn our attention towards some other caves.