TERRA INCOGNITA: The 2001 Cerro Rabón Expedition, Mexico

By Todd Warren, published in NSS News, April 2002

From the shelter of our base camp we watched it roll in: angry black storm clouds boiling across the lowlands of the plateau and moving towards us at speed with dark, unleashed fury. Within moments, heavy drops began pummeling the base camp roof. We knew the satellite team was directly in the eye of the storm. We knew they were eating water...

In early February, the 2001 Cerro Rabón Expedition Team converged on the town of Huautla, in south central Mexico. Our 13- member team consisted of an experienced crew of cavers from the United States and Europe: Evan Anderson, Chris Andrews, Mike Frazier, Suzette Kane, Daniel Laos, Steve Lester, Randy Macon, Patricia Malone, Todd Warren, and Aaron Zumpf (Colorado); Tom Malabad (Virginia); Nick Zegre (North Carolina); and Jacqueline Feyerer (Germany).

From Huautla, our journey would proceed on into the cloud-forested Cerro Rabón Plateau, located in the Sierra Mazateca Mountains of Oaxaca. This remote and dramatic limestone plateau is located about 300 kilometers southeast of Mexico City at an elevation of over 2,000 meters. The region has played host to international caving expeditions on nearly every other year since 1987 (Proyecto Cerro Rabón). The Cerro Rabón Project has explored and recorded more than 120 caves during the previous thirteen years, including the significant discovery of the Kijahe Xontjoa ("The Forgotten Door"), a yawning subterranean system currently over 1,200 meters deep. In addition to speleological exploration, Proyecto Cerro Rabón has conducted extensive field observations on the hydrology, geology, geomorphology, biology, and archaeology of this fascinating region.

The goal of the 2001 Expedition was to investigate the largely unexplored southern quadrant of the Cerro Rabón Plateau, coined the Terra Incognita. Our reconnaissance would be focused on locating potential new caves among the giant limestone sinks and depressions blanketed by the dense rain forest.

We caught our first glimpse of this "Bobtail Mountain" on our approach along the mountain highway. The bone-white limestone headwall, surrounded by low clouds and reaching 1,500 meters above the valley floor, painted a surreal vista. Equally impressive was the idyllic view to the north of the Miguel Aleman Reservoir, an enormous body of water dotted with hundreds of tiny palm-covered islands, reminiscent of Southeast Asia.

plateau The Cerro Rabón plateau

We crossed a bridge over the Rio Oropan, a swift-moving river that blasts out of resurgence cave at the base of the mountain, at 20 cubic feet per second. The resurgence indicates the presence of a deep, hydraulic feeder system on the plateau above.

Our two-vehicle caravan proceeded up a rough and winding road past the town of Cerro Central, and finally to the tiny community of Rancho Avendano where we reached the end of the road. Literally. The ranch owners appeared curious about the arrival of these gringos, yet happily permitted us to park and camp by the side of the road. From here our journey would continue on foot, traveling along an extensive network of ancient trails used by the Mazatec Indians for centuries.

Our next order of business was to send an advance team with overnight packs to the outlying village of San Martin Caballero, the base of operations for the length of the expedition. A team consisting of Steve, Nick, Suzette, and Todd set out into the fading light of the afternoon on a quest to locate a Mazatec man named Senor Anselmo, the caver's amigo. Anselmo was our connection to rent a house in San Martin and arrange for the use of burros and mules to carry our monstrous burden of equipment up the seven kilometers of rocky trail to our base camp. The remainder of the team settled in for the night in a makeshift campsite among the cattle.

Nita Cein Nita Cein

By the light of the full moon, the advance team marched toward San Martin. On more than one occasion the map and compass was consulted to help guide their way along the sometimes-confusing network of trails. Finally the lights of the small village appeared in the distance. Hours after leaving the vehicles they arrived on the outskirts of town and discreetly asked directions to Senor Anselmo home. Ascending a grassy slope, they found themselves at the entrance of the casa, a traditional Mazatec home constructed of hand-sawn boards with a galvanized roof and dirt floor. Anselmo greeted them at the door with a friendly smile and invited them into his home. Conversation soon turned to the expedition and Anselmo described the various political problems he was experiencing with some of the towns people last year. He explained that he was unable to rent the building, known fondly as the "Rathouse," to the expedition team until permission was sought from the municipal authorities in the town of Tenango.

The conversation continued into the evening and Anselmo kindly invited the team to crash for the night in the Rathouse. They followed the man outside along a trail on a steep grade of limestone steps for nearly thirty minutes before arriving atop the bluff at a small hut. Anselmo unlocked the Rathouse and packs were dropped on the bare concrete floor. The small building has acted traditionally as a communal kitchen and storage house by expedition caving teams for many years. They bid Anselmo a "Buenos Noches" and rolled out the accommodations for the night, planning an early start the next morning to return with news for the rest of the team.

The southern region of the Cerro Rabón was revealed at first light the following morning. From the high vantage point on the hill, the advance team received an unparalleled view of the peaks and dolinas shrouded by kilometers of emerald-colored rain forest. The team arrived back at Rancho Avendano by late morning and conveyed the news to the rest of the group. Daniel and Aaron volunteered to make the lengthy trek to Tenango to secure permission for our planned stay in Son Martin Caballero. Mike and Randy also departed later in the afternoon to make final arrangements for gear transport while the rest of the team settled in for another night at the Ranch.

The next morning we were nearly awakened by the early arrival of half a dozen burros followed by their handler-evidence of a successful mission to Tenango! We wasted little time loading half of our equipment onto the backs of the sturdy beasts as the temperatures started to bake another fine, cloudless day. A tarp stretched over the truck provided shade until later in the afternoon when team members donned their additional packs and began the trek to San Martin.

When our team finally assembled in the small village, we began the process of organizing the Rathouse and started the all- important task of locating a source of water. The Cerro Rabón Plateau receives as much as five meters of rain per year, yet rainfall creates virtually no surface water, disappearing into the fissures and cracks of the porous karst landscape. The local people rely on cisterns to contain rainwater for long- term storage through the "dry" season. The search for agua was beginning to look increasingly bleak and our gringo crew was contemplating the merits of a rain dance ceremony by the end of the day. Our prayers were answered in the early hours of the next morning. The skies opened up and we experienced the first of a "Cerro Rabón deluge," with heavy rains all day long to fill our makeshift cisterns to capacity.

San Martin Caballero View of town from the Rathouse

Despite the soggy weather, a small team (Mike, Randy, and Patricia) geared up for an initial foray into the thick to begin exploration in Terra Incognita. A second team ventured out to explore and survey in the labyrinthine canyonland located in the hills above the Rathouse. Remaining personnel bided their time gathering and purifying water. The rain finally subsided in the late afternoon and both teams returned unscathed with the first survey data of the expedition.

In the days ahead, small teams departed camp in the mornings for long day trips to investigate several potential sinks indicated on the map. Travel through the rainforest was at times a daunting and potentially dangerous task. Forward progress was awarded through the efficient use of a machete, chopping trails through ankle-grabbing vines and lush foliage. Visibility was limited and the terrain underfoot was jagged and unforgiving.

Teams also had to be on the lookout for poisonous snakes and nasty nettle plants. Many sotanos were discovered on the northern edge of Terra Incognita during the first week, but upon survey, were discovered to be blind and ended in collapsed debris 20-30 meters deep.

Rest days at base camp were reserved for drawing up maps, repairing gear, conversing with the local people and learning a few words of the Mazatec language, purchasing food at tiendas in Son Martin, and reviewing basic first aid and intravenous therapy with our team nurse, Suzette Kane.

It was soon decided as a group that the most efficient method to reach the heart of the T.I. project area was to send a small satellite team deep into the jungle to investigate the most enticing dolinas indicated on the map. A four-person team, packing fast and light, with compact hammock shelters and minimal equipment could reach the target area in four hours. The first satellite team (Randy, Patricia, Evan, and Nick) spent three days in the southeastern T.I. and were able to establish a suitable campsite in the jungle, but were forced to drink from small fetid pools in a cave when water became difficult to locate. They were rewarded with several discoveries, including the longest cave surveyed on the expedition, Cueva de Aranas Negras (Cave of the Black Spiders).

Meanwhile, a second group traveled north from base camp loaded with gear to descend and survey a pit discovered near the trail to Tenango. Rocks tossed into the dark abyss sliced the air for five seconds before a booming echo sounded from below. The sotano, Nita Cein (Honey Pit), bottomed out at 81 meters deep in a large room with no continuing leads.

Two days later, a second team of Steve, Chris, Evan, Nick, Daniel, and Aaron departed in the afternoon for a return trek to the satellite camp to continue exploration. The remaining team members spent a rest day at the Rathouse. During the late afternoon we watched it roll in: black storm clouds boiling across the lowlands of the plateau and moving towards us at speed with dark, unleashed fury. Within moments, heavy drops began pummeling the base camp roof. We knew the away team was directly in the eye of the storm. We knew they were eating water.

The satellite team managed to locate their campsite through frantic efforts amidst near flood conditions, and was able to start a fire to begin drying out through the deluge. The following day they completed the survey of Cueva de Aranas Negras (107 meters) and continued exploration of the region.

When the satellite team had returned to San Martin Caballero, we decided to wrap up the expedition early. Despite the friendships we had created with many of the people during our stay, continued political problems with a few of the locals had left the team uneasy about spending any further time in the town.

Canyon Lands Pit in the Canyonlands area

Mike and Chris enlisted the services of a local Mazatec guide for one last grand push out to the southern edge of the plateau to investigate two more potential dolinas shown on the map. Their plan was to meet the rest of the team back down at the vehicles in two days. The two gringos loaded up their fat backpacks and followed the guide (carrying only a small burlap shoulder pack) down the trail. Two long days of hiking did not yield the "big one," but they did get an education in jungle survival skills. The guide taught them how to procure drinking water from vines and how to find natural fire starter from the sap of native trees.

All the team members arrived back down at Rancho Avendano on February 21st. We gave praise to the god, Oztotl, for a fruitful expedition and bid "Xat'alanga" (farewell) to the Cerro Rabón Plateau.

The 2001 Cerro Rabón Expedition was a successful reconnaissance trip to the Terra Incognita region. A dozen new caves were catalogued with a combined total of 647 meters of survey. The potential is rich for locating new deep cave systems on the southern plateau and the connection to the Rio Oropan resurgence remains elusive-for now.

Team 2001 The 2001 Cerro Rabón expedition team:
standing (L to R): Tom Malabad, Chris Andrews, Nick Zegre, Mike Frazier, Randy Macon, Jacqueline Feyerer, Steve Lester,
Front Row (L to R): Aaron Zumpf, Evan Anderson, Suzette Kane, Todd Warren, Daniel Laos (not pictured: Patricia Malone)

The 2001 Cerro Rabón Caving Expedition thanks our sponsors for their generous support: National Speleological Society, Dogwood City Grotto, Colorado Grotto, Southern Colorado Mountain Grotto, Mad Rats, Northern Colorado Grotto, Professional Land Survey of Colorado, Grand West Outfitters, Gonzo Guano Gear and Bob and Bob Enterprises.

Arenas Negras Cueva de Arenas Negras