Carroll Cave Upper Thunder River Camp Trip

• Date: July 8 & 9, 2023
• Location: Carroll Cave, Upper Thunder River
• Goals: Survey and perform map QC in Upper Thunder River
• Participants: Kohl Mitchell, Bryn Downes-Ward, Erica Hroblak, Caleb Mundwiller
• Time In: 9:30 AM July 8
• Time Out: 4:00 PM July 9
• Bio Count: ~20 cave fish, 4 isopods
• Report Written By: Kohl Mitchell

Our much-anticipated trip to the Lake Room and survey at Diarrhea Falls at the very end of Lower Thunder River had a wrench thrown into it when forecasts called for up to 2 inches of rain on Friday and Saturday in Camdenton. While the chances were pretty low, we decided that a 40% chance of death was too high, so we chose to change our objectives and make a trip to Upper Thunder River instead. This would be the first time cave camping for all members of our party, so the experience of camping was more important to us than the destination anyway.

Despite some issues with a low tire on my pickup in the morning, we weren’t too late getting to the cave, and were able to drop in right after Bill Gee’s team of 6, and just before Kristen Vogel’s team of 7. We quickly realized just how much of an impediment our 30-40 pound camp packs would be on our trip to the campsite, so the going was pretty slow – especially after we couldn’t just wade through the stream once we got past the Round Room. During our time wading through the stream, we counted approximately twenty cavefish.

The series of jumps across the canyon past the Bone Room presented a particular problem. We had to decide if we wanted to stick to the potentially deep water in the stream, or bother with repeatedly taking our packs off and passing them over the gap, since jumping with them on could be dangerous. We decided to begin with staying low, but the water became chest-deep before long and since we wanted to keep our wetsuits dry until survey started due to the wet passage we anticipated surveying in, we decided to climb a little higher and try to stick to a muddy middle level. However, it wasn’t long before this middle level disappeared and we had to choose between going high or low. This time, we chose high, and with just a couple more jumps to do before the passage got easier to navigate, we made our way through without too much trouble.

In the past, the few camp trips that took place in Upper Thunder camped at the Round Room; however, we decided to camp closer to the objectives around the Breakdown Barrier to maximize our survey time on Saturday. We had heard about several dry areas to the side of the main stream, and we passed several before finally seeing one that looked optimal, at station U184. We set our campsites up and had a quick bite to eat before we set off through the Breakdown Barrier, which turned out to only be a few stations away from our campsite. None of us had ever been in this section of the cave, so the maze of fallen rocks took us quite a while to navigate – although, we all agreed that it was pretty cool passage. We particularly enjoyed a section of broad, flat boulders that had fallen in a pattern that resembled a highway towards the end of the barrier.

For the main objective, we were sent to investigate the stream at the end of the cave. It was suspected that a small side stream cutting off from what appeared to be the main stream about 100 feet before the end of the cave could, in fact, be the main stream passage that carried most of the flow to Thunder River in this area. Our job was to investigate this stream and follow it wherever it led. As it turned out, the original surveyors got it right the first time. The little stream on the right side of the passage is just a tributary of the main passage and is honestly more of a series of stagnant puddles than a stream. I pushed the side stream a little further than is indicated on the sketch, but it quickly chokes off into non-human sized. Besides adjusting the sketch a little to better match up with the stuff before it in the area of the side stream, we didn’t see anything that needed changed here. We also investigated the main stream for a couple hours all the way from before the waterfall to Tony’s End, where the passage sumps to the ceiling, and saw no leads. There’s one spot 20 feet beyond the waterfall where a breakdown block landed on the stream and makes it look like it Ys off, but looking from behind the breakdown it’s obvious that it’s just the stream finding a path around the block.
On our way back to the campsite from the end, we did some brief QC on the main passage sketch and filled in some empty walls around the stream passage in a couple areas.

Finally, we looked at two dome leads indicated in the U186 side passage – both are sketchy breakdown climbs that lead to rooms with no going passage off of them, although the first one drops down to passage below in a second spot just to the right of the climb. We couldn’t find any survey stations in the side passage, and it wasn’t worth running an entire new survey line to the domes, so we just sketched the domes on top of the old sketch here as well. These domes were incredibly sketchy, especially the second one, which only Caleb climbed. Now that they’re on the map, there’s no reason for anyone to visit them again.

With our three main survey objectives completed, we retired to camp, making this the only successful survey trip I’ve ever been on that didn’t require a single survey shot. Interestingly, on our way back through the Breakdown Barrier, we noticed a breakdown boulder that appeared to have oxidized iron deposits on it. We all tossed and turned a bit through the night, but overall we seemed to get decent rest. We woke up at about 8:00, and took our sweet time getting up and breaking camp, since our only objective today was to get out of the cave before the rescue parties were called.

We actually made better time getting out than we did going in, because we stuck to the upper level through the jumps. Even though we had to repeatedly bucket-brigade our packs across the canyon, the obvious trail through this area made it far easier to make sure we were on the right path, and we didn’t have to worry about climbing up and down between levels this time either. We had initially planned on making a trip to Convention Hall on the way out, but by the time we passed the way to the Hall, we all had entrance fever and were ready to be out.

The wade through Upper Thunder between the Round Room and the T-Junction felt like a stroll in the park compared to the passage we’d been dealing with for the past couple of hours, and it felt like no time at all before we were climbing back up the shaft. After winching our gear up the shaft and locking up, we headed to Camdenton for a delicious burger at a questionable local bar.

Overall, despite the fact that our survey objectives were generally a bust, we all had a great time camping, and are looking forward to the next time!