12/25/21: PEP Trip Report - An Untraditional Christmas in Sistema Purificación

Updated: Mar 24

By Ethan Perrine

Christmas morning in the Canrado Castillo field house found a team of cavers pouring over maps at Gill’s dining table. I entered and crossed the room toward the high shelf where my animal crackers were hidden. Breakfast in hand, I sat down to join the fold. Bev Shade was studying the maps for Oyamel and Allarines, while Matt Olifant and Nancy Pistole flipped through survey notes of Valhalla, a section of Sistema Purificación near the field house. I had been there a few days earlier and agreed to guide Matt and Nancy to the first marked station after which I agreed to join Mowgli for the day’s primary objective. We scattered to pack snacks and I met Matt and Nancy to begin our hike through the village. A brisk ten minute walk later I was squirmuing through the narrow boulder entrance, using my body to check for snakes. Soon the three of us were off and moving. I soon realized that I had condensed the route in my head...considerably. If you’re wondering if I am referring to the route to the cave, or the route in the cave, that’s correct. I had told Bev I’d be back in 20 minutes which we’d already spent on the walk there. So, I ushered them further and further, twist after turn after squeeze after climb, and occasionally rounded the corner to dart ahead and covertly confirm that I was not leading us astray. Finally, I saw a familiar station that I had set days prior and bid them adieu after agreeing on a callout time.

I tore back to the entrance as fast as I could and got out at 11:14. I sprinted back to the field house where I was relieved to find Bev still showing route information to Mowgli for our day’s objective. We were going to rig Oyamel through the Lower Pit Entrance, all the way down to -82m at the Slit Pit. Simultaneously, Bev and Sean were going into Allarines to bust through a dig constriction at the bottom. They intended to come out through Oyamel, and we were meant to be waiting for them. This would add Allarines to the extent of Sistema Purificación, which Oyamel already connects to. As we stood over the map, I took note of all the blue water drawn in nearly every passage. I am sensitive to the cold and wasn’t bringing my wetsuit so I wondered to myself if I would get wet that day. Mowgli and I set off for the cave, which was just a short short walk from the field house in the opposite direction of Valhalla.

We remarked on how pleasant the path was and chatted while we meandered along the GPS route. Upon reaching the supposed coordinates at the base of a towering limestone henge, we struggled to find any signs of a cave entrance. We scoured the area inside, around, and above the henge and after a hunt that left us with GPS track resembling spaghetti, found a sink with a pit and decided that we were probably in the right spot. We stood overlooking a 20-25 foot deep drop, shaded by two sturdy oaks. I rigged to a branch and Mowgli went down to find out if there was passage at the bottom and if so, if it matched the map. He whooped in the affirmative and soon we were both at the bottom facing a duck under.


Mowgli is a caver of many skills, but he said way finding was one he needed to work on, so I followed his lead. Even if I had been leading the way, none of my map reading experience had prepared me for the multi level Gordion knot of a cave that we were examing on his phone screen. The beginning of the cave was simple though, and confirmed that we were in the right entrance of the correct cave. We knew this because just inside the entrance room was a still, blue pool of water. I got the feeling that I may be getting an answer to my question about staying dry sooner rather than later. Mowgli lead the way and we carefully traversed along an archipelago of rocks that sat above the water line. We made it across with relative ease and I hoped out loud that all of the pools would be traversable.


Moving further in, my inner monologue was interrupted as I came face to face with a worm-shaped, transparent blob. It was attached to dripping flow stone on the wall and scanning around I could see several more. The blobs appeared to be a cocoon; within each one was a larva that freely floated in the iridescent goo medium. These were totally new to me, so I documented them and pulled myself away to catch up with Mowgli. He was beginning to climb around a waist deep plunge pool. Traversing successfully look grim and after a few moves Mowgli fell in. He made peace with it and waded to the other side. I on the other hand, was determined. I floated my pack and rope to the pool’s far side, and climbed along the slick holds protruding from the ceiling. As I crossed the halfway mark, the holds were smaller, fewer and farther between. I spanned the wall with my arms and was straining, hard. My trembling fingers slipped off the slick stone as I surrendered and slid in. My boots flooded, my pants soaked up to the thighs, and with them went my hopes of staying dry. I wrung out my socks in the next dry room and we checked the map. The drawn passages were spot on as we looked around and we were growing more confident with our navigation.

On the floor, much to Mowgli’s dismay, I spotted more intriguing fauna. Yellow and black Xystodesmid millipedes hidden in flood debris on the floor. I documented them too, again falling behind Mowgli as he pushed on. We regrouped and pushed on.


The cave had transitioned into an obstacle course of oily-black conglomerate that had long ago been shaped and smoothed. It led us to a lower level down what we believed to be “Apricot Pit.” This passage was just a line plot on the map and quickly proved to be much more convoluted that it appeared on paper. Horns stretched out from the ungulating walls, obscuring potholes and ceiling domes all of which distorted our echos and abilities to tell which way to go. We hunted for old flagging, leaving some of our own as we explored the unintuitive passages. Tubes branched, intersected, and branched again in multiple directions. We started to leave cairns at the ways we’d come through, then split up to collect reconnaissance on the possible routes ahead. There were fewer critters to keep me distracted and my lower half was getting cold. I wrung out my socks again, since every time I got them less than sopping, we would encounter another pool, and we stopped for a snack break. We looked at the map, just to humor outselves, and followed our instinct to go lower where possible.

Landmarks were few and far between, and when there were noteworthy obstacles, like a 6 foot long, 9 inch slot canyon squeeze, they were nowhere to be found on the map. Reluctantly we abandoned our reliance on the map and leaned into the ”when in doubt, try to go down” approach. Sure enough, we forged our own path that continued to lead us deeper and deeper. Several hours had passed by now as we snaked deeper and deeper when we rounded a corner and all of the sudden…. we found some bolts! We were on the right track all along, what a relief! 6:30 PM found us sitting atop what we believed to be ”Anchovy Pit.” We were discussing the Cheve expedition while Mowgli flaked rope to rig the drop. In the middle of his story, a sound caught my ear: the distinctive, familiar sound of a hammer striking rock. I exclaimed and we held our breath, waiting in expectant silence. We listened intently, eyes looking nowhere in particular; all attention was trained on the walls. ”Tap, tap, tap,” this time it was clearer, and we both heard it. It was close! Bev and Sean must have been right through the wall.

Despite the warped acoustics of the Swiss cheese passage, we were confident in the direction and Mowgli used his climbing hammer to send a burst of taps back in reply. We were right on the money, we had to be! Our spirits soared with the promise of imminent connection and we hastily rigged and descended to the next lower level in the direction we heard them, pounding on the walls and looking for leads. We hammered, listened, then hammered again. Nothing. “Maybe they were hammering an obstacle on the way to the lead,” we reasoned. We both knew we were losing time and needed to capitalize on this window of apparent closeness. Mowgli climbed up to a higher level, pushing leads and shouting. I descended the lower levels through smaller pits, slamming rocks into the walls. Hammer, listen, repeat. eventually I ascended back up Anchovy, and sat against the wall, listening for replies as Mowgli pounded on the walls. Now I was proper cold, shivering in my gravel filled boots. We went on like this for 2 and a half more hours, until finally our head out time of 9:00 PM arrived. We ascended the upper pit, spirits lowered by the confusing radio silence. My feet, and the rest of me, were continually soaked as we backtracked.


We retraced our steps, passed our flagging, and quietly made our way an hour and a half to the exit. We emerged, in the dark at 10:30 PM, waterlogged and grateful for the warm night air. We started back on the GPS track to the field house, but decided to stay on the road we’d unnecessarily deviated from on our way in, missed a turn, and wound up at the base of the hill where the field house was. ”Fuck it” was the mutual sentiment, so we just cut up into the trees and fortunately stumbled onto an animal path that lead to the Brinco trail. We sloshed passed the reflective tags and finally made it back just after 11:00 PM. The field house was dark so I peeled off my freezing shoes and top layers and clambered through the door. To my surprise, Bev and Cathy were waiting up for us. I had questions! Where were they, did they hear us, did did they breakthrough, and most of all, when did they turn around? Bev told us that they had busted into virgin passage but it soon ended in a sump and they left at 6:30 PM. I stared at the wall and had to laugh. That meant we had heard them right when they were leaving and subsequently spent 3 hours trying to communicate with an empty cave. Oh well. I was so glad to be dry and I had enough service to ask about how Holly’s day was. At the table, Cathy treated us to stuffing, gravy, and mashed potatoes, and I had oatmeal for desert. All told, it was a Christmas I won’t soon forget.






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