Search and rescue is a broad term applied to a variety of operations focused on locating and assisting persons who are in danger or distress. Search-and-rescue operations are conducted by many different organizations, from local law enforcement agencies to international humanitarian organizations, and specific search-and-rescue techniques have been developed for many different situations, from land searches for survivors of disasters (such as earthquakes or floods) to searches for ships or persons lost or in distress at sea. Although search-and-rescue operations may recover property as well as persons, the highest priority is generally accorded to saving lives of those in distress while also safeguarding the lives of the search team.
Given the vast area covered by the world's oceans and the fact that much of this area is far from both territorial waters and established shipping lanes, international cooperation is key to maritime search and rescue. The International Convention for the Safety of Life at Sea (SOLAS), adopted in 1914, was the first international convention to deal with issues of maritime search and rescue, along with many other safety issues. The SOLAS convention deals with many aspects of maritime safety, such as ship construction, radio communications, and securing of cargo, and it has been modified and amended many times since 1912, when it was motivated after the sinking of the Titanic. Chapter V of SOLAS is the section most relevant to maritime search and rescue, as it spells out the obligation of ships to respond to others in distress. The rules of this chapter apply to all ships, including fishing vessels and private boats, while many of the other regulations in SOLAS apply only to merchant vessels.
The International Convention on Maritime Search and Rescue was adopted in 1979 and came into force in 1985; this convention builds on the obligations specified in SOLAS for one ship to assist another in distress, and it establishes an international system of maritime search and rescue. After adoption of the convention, the International Maritime Organization began the process of dividing the world's oceans into 13 search-and-rescue areas, with each party to the convention being responsible for specific regions; this process was completed in 1988. Parties to the convention agree to a number of obligations, including establishment of a basic search-and-rescue service, creating rescue coordination centers to be operated 24 hours per day, coordinating search-and-rescue operations with neighboring states, establishing detailed plans for search-and-rescue operations, and continuing a search until there is no reasonable hope of rescuing survivors.
In land search and rescue, as in maritime search and rescue, the total area to be searched is generally divided into segments, with different segments assigned to different teams. Certain pieces of information can help guide and limit the search. One such piece is the point last seen (PLS), which is the last place a witness reported seeing the person; this information is useful because it helps establish the total area to be searched. For example, if a hiker was seen at a particular point, it is possible to calculate an upper limit for how far he or she could have traveled in the time since the sighting. The concept of the last known position (LKP) is similar but does not require eyewitness identification, so may thus lack the time component of the PLS; however, an article of clothing or a unique shoe print could identify a location as one the person being sought had passed through.
Several different search methods have been developed for land search and rescue; some require trained searchers, while others can make use of average citizens without particular training or expertise. The probability of detection (PoD) in a particular case refers to the likelihood of finding the subject with a particular search method. Generally speaking, more thorough search methods have a higher PoD but are also more time-consuming; organizing a search for a (presumed) living person often requires a trade-off between the most thorough methods and the quickest methods, to avoid locating a corpse rather than a live human being. A grid search, in which the search team forms a line and moves slowly through the search area, is a thorough but slow type of search; a trained team can cover one mile in about 3.5 hours. Keys to a successful grid search are maintaining even spacing among the team members and covering all the areas assigned while not avoiding difficult areas, such as patches of thorns. A hasty search takes the opposite approach: a small team of trained researchers moves quickly through the search area, looking for clues of the locations of a lost person. Hasty searches are most useful when a high-probability area has been defined—essentially, when there is a high probability that the missing person is within that area. In a bastard search, the search team looks in the obvious places for the missing person; this type of search is often combined with the strategy of containment, in which searchers station themselves in locations where the lost person is likely to appear, such as along a road.
The use of trained search dogs is an important tool in many search-and-rescue operations; in the United States alone, there are over 150 canine search-and-rescue units. Canine search and rescue takes advantage of dogs’ sensitive sense of smell and the fact that both living and dead human beings emit scent particles that can be detected by a trained dog. Normally, teams consist of a search dog and handler, and each team is assigned to systematically cover a particular segment of the area to be searched. Canine search-and-rescue operations have several advantages: because they rely on their sense of smell, dogs can work effectively at night and in heavily populated areas, and they are effective even in situations where sight is limited, such as heavy forest or in the debris left by an earthquake, tornado, or flood.
Robots are often used in search-and-rescue operations in hazardous environments such as damaged buildings, when the lives of human and canine searchers could be imperiled by entering the structure to search for victims. A search-and-rescue robot is typically equipped with a camera and/or sound-sensing equipment, providing information to human searchers who can remain in a safe zone outside the area of collapse. Search-and-rescue robots can maneuver in spaces too small for either humans or search dogs, move in zigzag patterns, and be mobilized to any point in the search site, increasing the probability of quickly locating victims near the center of the area; normally, human and canine searchers work from the perimeter inward. Robots can also bring food and water to victims, increasing their probability of survival.
The Oklahoma City bombing in 1995 increased interest in using robots for search and rescue. They were not used in that disaster, but many researchers suggested ways they could have been employed. The World Trade Center (WTC) bombing in 2001 is the first documented case of using robots for search and rescue. In that crisis, robot search and rescue was coordinated by the Center for Robot-Assisted Search and Rescue and included scientists from universities, military operations, and private companies.
Search-and-rescue missions are often carried out under hazardous conditions, such as during storms at sea or through partially collapsed buildings following an earthquake. Because the goal is generally to minimize loss of life, hazards to the rescue team must be balanced against the possible lives saved through survivor rescues. Because no organization has unlimited resources for search-and-rescue missions, the optimal use of those resources is also an issue in planning and evaluating search-and-rescue efforts.
The U.S. Coast Guard has established a performance benchmark to evaluate its efforts in saving lives. Although the Coast Guard's mission is maritime safety, the general principles of this benchmark can be applied to other types of search-and-rescue efforts. The benchmark is calculated as a percentage using the following equation:
LS / (LS + LLB + LLA + LUF)
where LS = lives saved, LLB = lives lost before notification, LLA = lives lost after notification, and LUF = lives unaccounted for. From 2008 to 2013, the Coast Guard's goal for this benchmark has been in the range of 76 to 78 percent.
The Coast Guard has also established two more specific benchmarks. One is the percentage of mariners in distress who have been saved after the Coast Guard has been notified. This benchmark is calculated as
LS / (LS + LLA + LUF)
where LS = lives saved, LLA = lives lost after notification, and LUF = lives unaccounted for. Because lives lost before notification is removed from the denominator of this statistic, it returns a higher percentage of lives saved. From 2008 to 2013, the Coast Guard's goal for this benchmark has been in the range of 83–84 percent.
A third benchmark refers to property and is calculated as
PS / (PS + PL + PUF)
where PS = property saved, PL = property lost, and PUF = property unaccounted for.
Annette Adams and colleagues undertook a study to derive a rule to help decide how long search-and-rescue missions should be continued. They examined all search-and-rescue missions in Oregon from 1997 to 2003; a decision rule was developed on missions from 1997 to 2000 (1,040 searches involving 1,509 victims) and validated on searches from 2001 to 2003 (1,262 searches involving 1,778 victims). They found that nearly all missing persons still alive were located within 51 hours, and that by 100 hours, nearly all living or deceased missing persons had been found. They also found that land searches were more likely than water searches to locate survivors, and that missing persons age 60 or older had a lower probability of being found alive. Although over 99 percent of missing persons still living were found in 51 hours or less, over half (56.6 percent) of longer searches also located a survivor, suggesting that not all searches should be abandoned at 51 hours, but that the search manager should consider factors such as the age of the missing person and whether the person was missing on land or on the water.
- Avalanches and Landslides
- Federal Emergency Management Agency (FEMA)
- Public Safety Canada
- State Emergency Management Agencies
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Search and rescue is an operation mounted by emergency services to locate and retrieve people believed to be in distress. Although the term...
A mission mounted to locate and assist a person or vessel in distress.
A U.S. Coast Guard system that coordinates ocean search and rescue efforts. Based on a worldwide plot of merchant vessel locations.