An afternoon thunderstorm caused flash flooding in Horse Cave, Kentucky, Thursday, trapping 19 people inside a cave. Trapped group escapes Kentucky cave through neck-deep water https://t.co/EXDpt81XGX pic.twitter.com/E1aj9CauMX — WTOP (@WTOP) May 27, 2016 On Thursday morning, students from a Clemson University geology course embarked on a guided tour of the Hidden River Cave, which only has one way in and one way out.