Caving and Cave Rescue

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Chapter 46 Caving and Cave Rescue

Caves are among the most awe-inspiring natural wilderness features remaining on Earth. Finding virgin territory within a few miles of major cities worldwide is breathtaking. Unlike the far reaches of space or deep trenches of the oceans, uncharted caves can be explored by any reasonably fit person, without a plethora of fancy equipment.

Caves are found on every continent in a wide array of forms. There are limestone caves, lava tubes, ice caves, marble caves, shelter caves, and water-filled caves—the variations are endless. Full of beautiful formations, strikingly odd structures, and mystical allure, caves have intrigued man since prehistoric times. From the practical use of caves as shelter to the sheer exhilaration of sport, the physical challenges of caving and rare environment found in caves set them apart.

Cavers are people who thrive on the prospect of exploring deep canyons and pits within the earth. Fascination with the unseen, the thrill of the frontier, the personal challenge of confronting the unknown, and the very darkness itself offer a distinctive aroma of adventure.

Caves can contain hostile environments. They present physical challenges such as water obstacles, extreme temperatures, confined spaces, exposure to heights, and hazardous surfaces varying from slippery mud to jagged calcite that can catch or snag on cavers’ clothing. Atmospheres can contain dangerous levels of carbon dioxide, methane, or hydrogen sulfide. Unusual pathogens, such as Histoplasma capsulatum, Leptospira species and rabies virus, are more likely to be found in caves. Well before engaging in underground duties, medical and rescue professionals should become thoroughly familiar with the harsh realities of the cave environment and anticipate unusual diagnoses in patients who frequent caves (Figure 46-1). Underground risks, both physical and medical, can be avoided or mitigated.

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FIGURE 46-1 Litter in tight spot.

(Courtesy Kris H. Green.)

Even experienced cavers can quickly find themselves in unexpected trouble. Such was the case for Frank and Jim, two experienced cavers who explored a seldom-visited side shaft within an extensive cave in Georgia. It took Frank and Jim 3 hours to walk up the mountain, negotiate the cave entrance, climb down into the cave, traverse several hundred feet of passage, rig and rappel a 38.1-m (125-foot) pit, travel across several hundred feet of additional passage, and then rig a side shaft that ran parallel to the cave’s main 178.6-m (586-foot) pit. Once down the shaft, Frank walked across a large rock slab. It shifted from his weight, and his lower leg was quickly pinned between the slab and the shaft’s wall. Frank’s lower leg was crushed, with pieces of bone sticking through an open wound. Over the next hour, Jim helped free Frank’s leg and did his best to stabilize the injury and make Frank as comfortable as possible. Realizing Frank would be unable to climb the more than 167.6 m (550 feet) of rope back to the surface, much less walk and climb through hundreds of feet of horizontal passage, Jim exited to seek help, leaving Frank alone, injured, and in great pain.

With the grim realization that he was now solo-caving and in extreme peril himself, Jim carefully climbed the pits and left the cave as quickly as possible. Once down the mountain, he drove to town and notified local authorities.

Fortunately, the incident had occurred in a region of the country where an experienced cave rescue team was available. The team was called out and a response initiated. The first rescuer reached Frank about 7 hours after the accident. It took another 9 hours to get Frank up and across the pits and through the entrance passages using hauls, highlines, and team hand-carries. Next came a 30-minute four-wheel–drive trip off the mountain to the waiting ambulance. After a short 15-minute ambulance ride, Frank arrived at the nearest hospital. The rescue involved about 50 people, both inside the cave and above ground; total time was 17 hours from the time of the accident to the emergency department.

Rescuers responding to a caving accident must be fully aware of the unique challenges involved. Approaching a rescue situation with the idea that a cave is merely a dark version of a typical wilderness environment is at best naïve and at worst a recipe for disaster. As for any environment, potential cave rescuers should be trained, experienced, and adept in functioning on their own in the cave environment before assuming any sort of active rescue role.

The first thought that enters the minds of many newcomers to caving is “claustrophobia.” In fact, claustrophobia is usually less of a problem for cavers (even new cavers) than are such issues as physical agility, route finding, endurance, and maintaining optimum performance levels in cold, wet, and confined surroundings. Learning to cope, indeed to thrive, under such circumstances is a prerequisite for the challenges of cave rescue.

Not only must cave rescuers be adept at managing the unique trials of functioning in the cave environment, they must also manage a unique set of rescue problems related to safety, equipment, logistics, access and extrication, and mission support.

A cave rescue should be initiated only with the direct and intimate involvement of qualified cave rescuers. Rescuers without cave experience, or cavers without rescue experience, are not sufficient resources with whom to launch a cave rescue. The demands of these two avocations are daunting enough individually; combined, they require physical conditioning and technical skills that are indeed humbling.

In addition to experienced ground personnel, the incident commander must be familiar with or seek the advice of someone who is familiar with the unique challenges of the cave environment.

The time to learn about caving is not as a medic on a cave rescue. If there is any chance that one will encounter a cave rescue as part of his or her profession or avocation, time should be spent becoming familiar with caves and caving techniques before the need arises for a rescue.

Environment

Any natural opening in the earth large enough to enter is considered a cave. Caves are similar to human-made mines and tunnels only in that they share a subterranean setting. On a practical level, mines and tunnels must be approached with skills, equipment, and training that differ from those for caves. This chapter addresses only natural caves such as may be found in a wilderness environment, not their dissimilar human-made counterparts.

Caves take many forms, including sinkholes, cracks, sumps, siphons, springs, pits, and caverns. The precise geology of cave formation is a more complex and diverse topic than can be adequately addressed within the confines of this chapter. Some caves are simply topographic in nature—cracks and fissures that are a natural result of typical geologic features. Included in this category are lava tubes, which form when a volcano erupts and lava flows away from its center. Gases create bubbles in the molten rock, leaving voids as it hardens. Lava tube caves form as flowing lava cools hard on the outside and continues to flow on the inside, leaving a “tube” of passage. Like most caves that are formed as a result of earthen upheaval and movement, lava tubes are unpredictable and may run for long distances or be limited to short passages and isolated rooms.

More interesting is the geology of caves that form over long periods of time. An oversimplification of this formation process is that caves—particularly limestone caves, but in truth any cave found in carbonic rock—are most often formed as a result of solution reaction between water, carbon dioxide, and the rock. Known as karst, such topography is formed when carbon dioxide and water combine to form weak “carbonic acid,” which in turn dissolves the carbonic rock. This process is most commonly found in limestone areas.

As the limestone dissolves, the acid solution follows the path of least resistance through the earth, and eventually pits are formed, then fissures, and eventually passages. When the calcium carbonate–infused water reaches a large enough opening, the carbon dioxide dissipates and the calcium carbonate is deposited as stalagmites (icicle-like columns protruding from the ground) and stalactites (icicle-like columns hanging from cave ceiling).

Sumps, siphons, and springs are all names that describe specific features in water-based cave formations. Springs, which are outflows of water from the earth, are obvious access points between underground passage and the surface, but they can be called a cave only when they are large enough for a person to enter.

Springs differ from siphons in that springs outflow water, whereas siphons take in water. Air-filled cave passages that terminate in water-filled passages are known as sumps. Some sumps are only a few feet long before returning to air-filled sections; others can be thousands of feet in length and may never resurface.

Sinkholes, cracks, pits, and caverns are terms that describe passages. These may be wet or dry and are differentiated by their shapes and attributes. Sinkholes, also called sinks, are formed when bedrock above a void collapses. Sinks may manifest as a sheer vertical opening into a cave with a well-like or open-air pit entrance, a steep sloping depression with a cave entrance, or a shallow depression of many acres that may not have more than a small, impassable sump to the cave below.

Cracks are narrow vertical passages formed as the carbonic acid solution finds its way through the ground. These are usually, but not always, developed along a joint in the rock.

The term pit refers to a vertical cave passage. Pits can be found both inside caves and at the surface. Most open-air pits form when the roof of a sinkhole collapses. Pits can also be formed by solution reaction or erosion of passage by flowing water.

Solution caves formed in soluble rock are the most common type found on Earth. Depending on local weather conditions and length of time, caves can take up to tens of thousands of years to form to the point where humans can enter. Caves are always getting either larger through solution and erosion or smaller by filling in with sand, mud, and fallen rock. These changes usually happen so slowly that they are seldom noticeable.

Most cave ceilings and walls are relatively stable. Large breakdown blocks of fallen ceiling and wall rock are often found in caves, but the chances of rock falling precipitously are slim. Breakdown usually occurs suddenly as a result of a major environmental event, such as an earthquake, or very slowly over years as the supporting rock below slowly degrades. Smaller rocks and rock slopes, often the results of ceiling and wall breakdown, are actually the greatest dangers in caves. Because they have not been stabilized by frequent travel, these slopes can shift and slide underfoot.

The continuous conduit leading through a cave is known as a passage. Passages can be huge, with room dimensions so large it is difficult to see distant walls (Figure 46-2) even with a light, whereas just around the next corner, the passage can change to tight impenetrable cracks or a dead end (Figure 46-3). Some cave passages wander around in a maze-like pattern that may total many miles in an area as small as a few acres of ground. Other caves may go for miles in the same direction and contain dozens of miles of passage. Many caves are only a few hundred feet long and have only low, tight, belly-crawl passage. A passage that opens into a wide area is called a room, whereas a tight, narrow passage may be further described as a squeeze or crawl.

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FIGURE 46-2 Typical large “room.”

(Courtesy Kris H. Green.)

Caves are formidable, dark, and often dangerous for the unprepared. Considering that running, seeping, or standing water originally formed most caves, it is not surprising that water is a major part of many cave environments. Cavers and rescuers must be prepared to negotiate anything from crawls in water-filled tubes (Figure 46-4) to underground rivers so large that a boat is required.

Caves that are no longer hydrologically active are called dry caves or dead caves because they are no longer in their formative state. Some caves are so dry that dust induces respiratory problems in cavers. Visitors to dusty caves should wear appropriate filter masks as a minimum level of protection from dust stirred up by the act of moving through a dry passage.

Temperature extremes are another common characteristic of caves. Caves tend to be at the mean ground temperature of the area. For the most part, U.S. continental caves run from cool to cold. Very warm climates, such as in Puerto Rico, sport warm caves, whereas alpine mountain caves in locations such as Montana measure close to freezing temperatures and may even contain ice. Caves found in tropical and desert environments can be so hot that cavers must wear lightweight garments to explore them—even then, these cavers are at risk for heat illness.

A common scenario in cave rescue is the concern for hypothermia. Most caves are cool to cold, but temperature differentials can exist within a single cave, depending on exposure, orientation, and water flow. Temperature differentials or pressure differences can result in winds flowing through cave passages. It is not uncommon for a caver to be supine or prone in 4 inches (1.6 cm) of 13° C (55° F) water with his or her back pressed against cold rock, facing a stiff breeze (Figure 46-5).

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FIGURE 46-5 Close contact.

(Courtesy Kris H. Green.)

If not prevented, hypothermia will complicate any cave incident. An injured, less mobile person will not generate as much heat as usual in the cold, frequently wet cave environment. Party members and rescuers must work to prevent hypothermia as soon as any injury occurs.

Rescuers must also protect themselves from hypothermia. A common scenario is for a rescuer to carry a load of heavy gear rapidly through the cave, then sit in a cold, wet passage to wait for the next assignment. The sweaty rescuer is now subject to evaporative, conductive, and convective heat loss. The well-prepared rescuer dresses in layers, travels light, and adds or removes layers of clothing as needed.

Caves can be fragile, often heavily decorated with mineral formations that have developed over thousands of years. Cavers try to protect these formations whenever possible by avoiding walking on or touching delicate areas or otherwise altering the cave. Even natural skin oils deposited by human hands can alter the growth of an active formation. The caver’s motto, “leave nothing but footprints, take nothing but pictures, and kill nothing but time,” extends to rescue operations. Everything brought in must be packed out at the end of the operation. An abandoned flashlight battery can leach its chemicals and poison cave-adapted life forms, ultimately destroying the cave and its environment.

Personal Safety

Whether entering a cave for exploration or for rescue purposes, cavers should follow personal gear requirements specifically tailored to caving. Clothing should be appropriate to the environment. Caves can be wet, dry, dusty, cold, warm, or a combination of these. The wind that can exist in passages makes chill factor a significant consideration. Undergarments should provide the necessary thermal layers and be made of a fabric that remains warm when wet. Layering undergarments provides the most versatile system of clothing.

Many cavers wear protective suits with a rubberized, vinyl-coated, or Cordura outer layer. In very wet caves, it is not unusual to find cavers in wetsuits. Coveralls, or one-piece garments with no exterior straps or accessories, help prevent snagging in crawls or tight passages. Ventilation is an important consideration in accommodating the varying degrees of exertion required in caving.

A mountaineering type of helmet, with a nonelastic “three-point” chin strap that keeps it planted properly on the head, is a must. The helmet protects against impact with the hard and often sharp rock of cave ceilings and walls in tight or low passages and offers protection against falling rock. The helmet is also a convenient mounting platform for the required light source (Figure 46-6).

It takes only one episode of trying to navigate in complete darkness underground to understand why every person entering a cave should carry no fewer than three light sources. Rescuers who are underground without functioning lights become additional cavers in need of rescue. Electric lights are preferred, but carbide lamps may also be used. At least two of these lights should be helmet-mountable for hands-free operation, each with sufficient “burn time” capacity or spare batteries to travel into and out of the cave. If carbide lamps are used, care should be taken when working close to patients, because it is easy in tight spots to forget that the light on the head is an open flame that can quickly burn anything with which it comes in contact. For this reason, most cave rescuers prefer electric lights.

Many cavers find gloves useful for both thermal insulation and protection against sharp rocks and sticky mud. Neoprene or rubberized gloves are popular choices, and scuba or sailing gloves offer durable protection. If the cave has vertical components, leather-palmed gloves are necessary for rope work. Ideally, a rescuer should carry different pairs of gloves for rope work and for negotiating a muddy passage.

Cave mud is slippery and adheres to everything. It makes walking and scrambling through a cave dangerous. Lug-soled boots provide the best traction, and stiff leather uppers help protect feet against sharp rocks. For small passages, or “crawlways,” a set of durable kneepads is a necessity, and many cavers use elbow pads as well.

Cavers, as any adventurers in a remote environment, should be self-sufficient and at least able to care for themselves for an extended period. This means being equipped with replacement batteries or carbide, potable water for drinking, food for energy, a basic first-aid kit, and extra insulation, such as thermal layers and a hat that can be worn under the helmet. In many caves, local ethics or regulations also require a “pee-bottle” and material for containing and removing solid waste. Cavers often store a folded trash bag in the suspension of their helmets to be used as an emergency shelter from wind and water, among other possibilities.

For the cave rescuer, the concept of self-reliance extends to being capable of caring for oneself, as well as a patient, for an extended period of time. Although the responsibility of patient care may be shared among several people, it takes planning to ensure that enough extra gear exists within the group so that the patient can be appropriately equipped and cared for.

Use a small, durable pack to carry extra gear. Because the gear will be alternately carried, pulled, pushed, and dragged through cave passages of different sizes, avoid excessively large packs with extra straps or external attachments because these can impede maneuverability.

Not all caves have vertical drops, but for those that do—or when in doubt—a lightweight seat and chest harness, descent device, and a rope-ascending system are essential. A rappelling device must withstand descent down a muddy or gritty rope. A brake bar rack, bobbin-type device, or sturdy figure-8 descender will do. Many devices designed for rock climbing are too lightweight to withstand these conditions repeatedly. In almost all in-cave drops, the caver will have to climb back up the rope. Thus an ascending system is essential. One or two 6-m (20-foot) sections of 25-mm (1-inch) tubular webbing come in handy for an extra step-up or to construct a quick belay or hand line.

Vertical caving is a highly specialized sport, and vertical cave rescue is even more specialized. The National Cave Rescue Commission offers courses in cave rescue, recommended for experienced vertical cavers.