Sumidero Resurgencias cave exploration!

My friend Rob was visiting from Seattle and with our must do trip to Cueva Zumbo accomplished the day before we decided to do some exploring. Tom and I visited the top of a sumidero (sinkhole) last year but we weren’t prepared for what we found at the time, this time we were. We hiked on some old overgrown roads to reach the sumidero. Just about every inch of Puerto Rico has been cleared in the past so there are roads, trails, and garbage just about everywhere.

This trip was fun because as far as we know this sumidero and cave is not well known. A map was created 30 years ago from a grad student but the copy we have is largely illegible. We arrived at our normal parking spot for the area only to find it chained off. We found a friendly neighbor who told us to park in his yard.

It took us about 30 minutes to hike to the top of this large sumidero. We could see that the other side drops 200 feet down. Fortunately for us the side we were on has eroded and collapsed enough to allow us a bit closer. I took my 100 foot rope and with a figure 8 on a bight put a tensionless hitch on a convenient tree. We were on a steep slope covered with bamboo, trees, and brush. We could not get close enough to the edge to see the bottom and we could not just throw the rest of the rope into the pit.

I volunteered to verify that the rope touched the bottom. I rappelled little by little uncoiling the rope as I went. I had to run it under some bamboo and logs. I reached a point where the drop was vertical and I threw the rest of the rope down. I saw that it just about touched the “bottom”. The bottom was a steep slope of loose rock but climbable. Down we all went. We still had to climb down another 75’ of steep rock and some old garbage to get to the cave entrance.

We get to the bottom and it was cold! This was a giant cold sink. It was dry and warm at the top and cold and wet at the bottom. We were all impressed with what we saw looking up from the bottom. All but one of us left our vertical gear here because we thought a through trip was possible. We went to the right and only got 100’ in before we found a lake of some green stagnant water. We were not thrilled to enter this cold dirty water so we took out the map and decided to try the other side. We got about 300 feet only to find deeper dirty water. We went back to the first lake and plunged in. It was cold and gross but I have been in much much worse water with Tom (Cerdio Inferneo, hog hell).

So we started in and the water was chest high for a while then it finally required swimming. When we got to the other side of this long tunnel the temperature got much warmer and we were on “dry” land again. We checked out some side passages and got to the end of the main tunnel. It ended with the resurgence of the Camuy river coming up from under the left side of the tunnel. It ran across the room and down another passage. The water flow was too strong to safely go down that passage (and come back) so we didn’t. We have had a good dry season so far so the water level is low and yet there was still too much water.

We got the highest C02 reading to date in this area, around 6Kppm. We spent a little time here not wanting to go back into the water. We finally made the plunge again and back we were at the entrance. Since we were already cold and wet we right away plunged into the lake on the left side. We explored the lake passage to the right a long ways, swimming most of it. Then back again to the entrance for a quick lunch. I was starting to shiver so I pushed for us to get moving again this time down the lake passage to the left.

This required swimming the entire way. We thought we would be treated to a small exit at the end that would lead to sunshine. We were not. Instead the passage got smaller and smaller and soon it was just a rock wall. There was a 10” by 8 feet long log floating there. I took it and felt around under the rock wall for an opening. I had to push the log about a foot down and then I was able to push the whole log through. That meant when we left the cave we would need to go see if we could find the log outside of the cave.

We made a quick retreat back to the entrance of the cave. We picked up our vertical gear and climbed out. We had a close call with a 100# rock but no harm done. We hiked back down to the dry river bed to find the log. We found where the cave must connect but there was no log. There must be a small sump in between. Looks like some SCUBA gear is needed to prove the connection.

This cave was much better than I expected with much bigger passages. Not a lot of formations and we were not prepared for all the swimming and cold water but it still was a great day!