Pit cave

A caver rappelling into Mexico's enormous pit cave, Sotano de las Golandrinas.

A pit cave (or vertical cave), often simply called a "pit", is a type of natural cave passage which is a vertical shaft rather than a horizontal cave passage. Pit caves typically form in limestone as a result of long term erosion by water. Pit caves can be open to the surface or found deep within horizontal caves. A pit is generally categorized as a vertical drop of any depth that cannot be negotiated safely without the use of ropes or ladders.

Exploration into pit caves requires the use of nylon kermantle rope or cable ladders. More specialized caving techniques such as the single rope technique (SRT) are common practice and the preferred method of pit exploration for cavers worldwide. The SRT involves the use of 10-11 mm nylon static rope and mechanical descenders/ascenders.

Pit caving

Vertical caving, also called "pit caving", is a specialized sport that should be undertaken only after acquiring knowledge of, and expertise in, proper vertical caving equipment and its use. For obvious reasons, vertical caving is more dangerous than "horizontal caving". Vertical caving requires the intimate understanding of ropes, knots, anchors, rappelling devices and ascending systems. Veteran cavers typically are knowledgeable in self rescue techniques including change-overs (the act of switching from rappel to climb while on rope) and pick-offs (the act of rescuing a stranded caver from their rope and returning them to the ground).

American caver Bill Cuddington, known as "Vertical Bill" and honored as the "father of vertical caving", developed the SRT in the late 1950s. Since the inception of SRT, specialized nylon ropes and vertical accessories have evolved, making vertical caving a far safer practice. The development of the rappel rack and the evolution of mechanical ascension systems in the 1970s helped extend the practice of pit exploration to a larger venue of established cavers.

Notable pit caves

• Sótano de Las Golandrinas ("Cave of Swallows"), San Luis Potosí, Mexico, at 1,094 feet, is the world's deepest freefall drop.
• Fantastic Pit, Ellisons Cave System, Georgia, USA, at 586 feet is the deepest freefall pit in the 48 contiguous US states.
• El Cap Pit, Alaska, USA, at 625 feet in depth, is the deepest freefall pit in the United States [1].
• Stupendous Pit, Rumbling Falls Cave, Tennessee, USA, this 202 foot pit drops into a 26 acre chamber, which is thought to be the largest subterranean room in North America.
• Hellhole, West Virginia, USA is historically important for vertical cavers. It's 154-foot entrance drop was the site of development of the single rope technique in the 1950s and '60s.