10/05-07/07 – Lower Thunder survey (Lerch)

Carroll Cave Survey Trip Report
Submitted by Bob Lerch CCC#140

Date: October 5-7, 2007
Areas Mapped: Lower Thunder
Cavers: Dan Lamping, Bob Lerch, Ben Miller, and Shawn Williams
Time In: 11:00p on 10/5 Time Out: 8:30 on 10/7

Duration: 45.5 hours

To meet our 2007 goal of surveying to the end of the three main trunk passages, we decided that a weekend camp trip was needed to continue our push to the Lake Room, the known end of the Lower Thunder River trunk passage. We entered late on a Friday night and made the obligatory 2.5 hour swim to Jerry’s Cairns. But don’t forget that there are some nice obstacles along the way, such as the Black Rock Riffles area in which you must carry your ~60 lb. pack for several hundred feet, and the Hell Holes at the downstream end of the Forevers. The Hell Holes is our name for the area of deep, muddy holes that are randomly dispersed throughout the last 500′ or so of the Forevers, just before the camp at Jerry’s Cairn. These 3-4 feet deep potholes of mud are treacherous, sending you face-first into the water on occasion.

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After some discussion about the most efficient use of time, we decided to do one very long day of surveying, rather than two shorter days. Some time around 1:00p on 10/6, we headed out from camp for the 2-3 hour trip to the end of the survey. Our tie-in station was D220, which was at least 2000′ from the Lake Room. The trip to the lead is a rather grueling 1.5 mile hike, with the last several thousand feet consisting of unrelenting, deep mud. We started the survey in the midst of this intensely muddy stretch, and we knew it was going to be a long, uncomfortable day. We split into two teams: Team 1, Ben and Shawn; Team 2, Bob and Dan. As usual, we did a leap-frog survey. Both teams enjoyed generally long shots in modest sized (20-30′ tall X 40-50′ wide) meandering passage all day. As we worked our way downstream, numerous leads appeared in the ceiling and at the top of the passage along corners. None of them could be accessed without aid as they were 15′-25′ above the floor of the passage. These upper leads may just be numerous truncated pieces of old phreatic passage, or there could be an entirely separate network of passages above the main trunk. Plans are being formulated to access these leads, but we weren’t going to see any of them today. We had a productive day of surveying, getting within about 250′ of the Lake Room, but we were too worn out after 14 hours of surveying to finish this last bit. By the time we got back to camp, it was 6:00a, and we had been caving for about 17 hours. Footage totals: Team 1, 762.4 ft; Team 2, 693.3ft; Total, 1455.7 ft. (0.28 miles).

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