TWENTY-FOUR
HE WAS CHEST-DEEP IN THE frigid water when he suddenly felt three sharp tugs. Though years to come would bring other close calls in caves, he would never again feel relief so intense. Rather than haul her back in a panic, as his own handlers had done, nearly bringing him to grief, he simply held steady on the rope so that she could bring herself back. Am Ende finally reappeared, cold and dripping but excited.
“It goes,” she announced. “I used all the rope. The swim is at least sixty meters. And there is a big river tunnel on the other side.”
That excited Stone, too, but the tight 200-foot passage that am Ende had just traversed made him uneasy. They had no way of judging the oncoming, or even current, weather. He knew that even light rains had sealed cavers on the far side of such passages before. Those victims had been saved either when the rains stopped and the water levels fell or by divers who’d rescued them. (In some cases, the divers had performed recoveries rather than rescues.) But if that happened here, as deep as they were in Huautla, there would be no rescue. And because it was now the rainy season, the water level would not drop—it would keep rising for weeks or even months, in fact.
There was nothing they could do to stop the rain, but Stone decided to at least rig a rope through the passage, thinking that they might be able to pull themselves back if it flooded. The security that rope offered was mostly psychological, because a rainy season flood that trapped them on the other side would almost certainly kill them. For one thing, without diving gear of any kind, they would have to come back through the flooded tunnel holding their breath. Making a cold, 200-foot breath-hold dive encumbered by packs and gear, even in open water, would be a small miracle in itself. But there was more. If am Ende got partway through and decided to abort, could she make it all the way back before her body’s autonomous carbon dioxide reflex made her gasp, drowning her? Coming second, Stone would have no way of knowing whether she had made it. (Pulling along a second rope behind her, as Stone had done back in ’79, would only increase her drag and the possibility of snagging; the margin for error was too thin here for that.) After waiting some reasonable amount of time, he would start through the passage, perhaps only to find her dead body blocking the way forward.
Nor was that all. A well-known phenomenon in physics called the Venturi effect dictates that when fluid flows from a larger area into a smaller, its velocity increases. Garden-hose spray guns work because they constrict the slower flow from the hose through the gun’s tiny nozzle. If enough water flowed down through Huautla to fill the preceding sump and force it through the smaller passage beyond, it would not be like a garden hose. Water would blast out of the passage’s far side as if from an open fire hydrant. Nevertheless, am Ende explored on by herself while Stone worked, and came back just as he was finishing the second bolt.
“Do you want the good news or the bad?” she asked.
“Give me the bad first.”
“I followed the water downstream past another lake. It turns into a sump. I swam the whole perimeter. There’s no way on.”
“So what’s the good news?”
She explained breathlessly that about 300 feet ahead of them, she had found a huge river pouring in from the left side of the cave with four times the flow of the one they had been following.
“Four times? That’s incredible.”
“Yes, but it leads upstream. That’s not the direction we want to go.” Unable to conceal her disappointment, she said, “I think we’re at the end of the road.”
“We’ll see about that,” Stone said.
It took them only about fifteen minutes of wading through shallow water to find the waterfall she had described. Stone, too, was amazed. It was the biggest waterfall he had ever seen underground. Water was jetting straight out of a hole in the rock that was easily 20 feet in diameter. Stone believed this was, at last, the mythical underground resurgence of a surface river, the Río Iglesia, for which two dozen expeditions had searched since 1967.
They pushed on, moving through a series of narrow, ascending rock passages that eventually deposited them in a monstrous room. It was about 330 feet in diameter where they entered, then narrowed like a funnel, down a 45-degree sand slope, to yet another sump, this one 165 feet wide and 80 feet long. It crossed the end of the chamber like the top bar of a T. They had hit the sump perpendicular to its long axis and about at its midpoint. The wall on the far side of the water was sheer and rose beyond the limits of their lights. Into this sump flowed all the water from all the waterfalls and rivers and channels and sumps and infeeders above them. There was only one name for it: the Mother of All Sumps.
Large transverse dunes crossed the 45-degree sand slope like giant steps, and they knew that only a truly monstrous flow (visualize Class IV rapids) could have sculpted sand, gravel, and rocks into ridges like that. Every rainy season produced just such torrents, which came roaring and boiling down the riverbed, carving its bottom and dumping everything into the Mother Sump. Am Ende and Stone were standing at the end of the barrel of an immensely long gun, one the rainy season could load and fire at any moment.
There was no way around the sump, no way through it or under or over it.
“Checkmate,” Stone said aloud.
STONE AND AM ENDE RETURNED TO Camp 5 without incident, then continued on to Camp 3 and out of the cave. Their accomplishment had no parallel in the annals of cave exploration—and few in exploration history, period. Years later, Stone was asked by a NationalGeographic.com interviewer to name the happiest moment of his life. His quick answer said worlds about what he and am Ende had endured during their extraordinary six days beyond the sump:
“The evening of May 6, 1994, toward the end of the four-and-a-half-month San Agustín Expedition. That was when, after 11 days underground in the Sistema Huautla caves in Mexico, my colleague Barb am Ende and I managed to make it back to Camp 3.” Their six-day Huautla effort was a monumentally stunning accomplishment, and yet Stone’s happiest moment came not during their exploration of the great cave but upon their escape from its darkest heart.
Stone had been seriously exploring the caves of Mexico for eighteen years, since his first true expedition in 1976 with Jim Smith. He had been on this expedition for almost three months and deep below ground on the last push for eleven straight days and nights. Based on measurements they made during their six-day foray, he and am Ende had established that Huautla, at 4,839 feet, was the deepest cave in North America. They had explored more than 2 miles of new passage, the entire time exposed to countless dangers and beyond any hope of rescue.
Their discoveries gave am Ende and Stone cause for rejoicing. But the ultimate goal still eluded him. The deepest cave in the world, just then, was a French cave named Réseau Jean Bernard, which, at 5,126 feet, was 287 feet deeper than Huautla. Thus ended 1994.
Well, not quite. Shortly after Stone and am Ende walked out of the cave, Outside writer Craig Vetter walked into the camp.