Over 350 miles of cave have been mapped so far, and some speculate the cave could have over 600 miles of corridors. While hundreds of people wander this vast cave on tours, Meiman often works on his research in silence, just miles away in the same cave network. But the cave is not totally silent. Meiman says subtle sounds, colors and weather patterns fill the cave, especially at the lowest levels, over 300 feet below the surface, where water wears at the limestone. Winds like the one that greeted McCombs on his first visit often billow through the tunnels.
Breezes can form as cool air settles to the bottom of connected cave tunnels.
This causes air to shift throughout the cave network. Local storms also lead to pressure changes at the surface that can create breezes within the cave. Like many caves, Mammoth cave stays at a pretty constant 53 degrees Fahrenheit, and is extremely humid. When a heavy summer rain brings a rush of warm water into the cave, the moist cave air condenses and an eerie fog forms in cave tunnels near the underground river and cave openings. During such fogs, Meiman imagines the early explorers in the cave, not understanding why fog had suddenly clouded their lantern light.