Types of Disasters and Their Consequences

American Public Health Association 

In This Article


Global statistics show that floods are the most frequently recorded destructive events, accounting for about 30 percent of the world's disasters each year. The frequency of floods is increasing faster than in any other type of disaster. Much of this rise in incidence can be attributed to uncontrolled urbanization, deforestation, and, more recently, the effects of El Niño. Floods may also accompany other natural disasters, such as sea surges during hurricanes and tsunamis following earthquakes.

Except for flash floods, flooding causes few deaths. Instead, widespread and long-lasting detrimental effects include mass homelessness, disruption of communications and health care systems, and heavy loss of business, livestock, crops, and grain, particularly in densely-populat-ed, low lying areas. The frequent repetition of flooding means a constant, or even increasing, drain on the economy for rural populations.

Flood-related mortality varies from country to country. Flash flooding, such as from excessive rainfall or sudden release of water from a dam, is the cause of most flood-related deaths. Most flood victims become trapped in their cars and drown when attempting to drive through rising or swiftly moving water. Other deaths have been caused by wading, bicycling, or other recreational activities in flooded areas.

The stress and exertion required for clean up following a flood also cause significant morbidity (mental and physical) and mortality (e.g., myocardial infarction). Fires, explosions from gas leaks, downed live wires, and debris can all cause significant injury. Water-borne diseases (e.g., enterotoxigenic Escherichia coli, Shigella, hepatitis A, leptospirosis, giardiasis) become a significant hazard, as do other vector-borne disease and skin disorders. Injured and frightened animals, hazardous waste contamination, disruption of sewer and solid-waste collection systems, molds and mildew, and dislodging of graves pose additional risks in the period following a flood. Food shortages due to water-damaged stocks may occur due to flooding and sea surges.

Educating the public about the dangers of floods and about avoiding risky behaviors may prevent deaths. Since most flood-related deaths are due to drowning in motor vehicles, educational campaigns can discuss how cars do not provide protection from moving water and that as little as two feet of water is capable of carrying vehicles away.

Even more important to injury and disease prevention is education regarding clean up procedures and precautions. Rubber boots and waterproof gloves should be worn during cleanup. Walls, hard-surfaced floors, and many other household surfaces should be cleaned with soap and water and disinfected with a solution of one cup of bleach to five gallons of water. Surfaces on which food may be stored or prepared and areas in which small children play must be thoroughly disinfected. Children's toys must be disinfected prior to use or discarded. All linens and clothing must be washed in hot water or dry cleaned. Items that cannot be washed or dry cleaned, such as mattresses and upholstered furniture, should be air dried in the sun and then sprayed thoroughly with a disinfectant. All carpeting must be steam cleaned. Household materials that cannot be disinfected should be discarded.

Residents must understand that flood water may contain fecal material from overflowing sewage systems as well as agricultural and industrial byproducts. Although skin contact with flood water does not by itself pose a serious health risk, there is some risk of disease from eating or drinking anything contaminated with flood water. Anyone with open cuts or sores that could be exposed to flood water must keep these areas as clean as possible by washing with soap to control infection. Wounds that develop redness, swelling, or drainage require immediate medical attention.

Routine sanitary procedures are essential for disease prevention. Hands must be washed with soap and water that has been boiled or disinfected before preparing or eating food, after toilet use, after participating in flood clean up activities, and after handling articles contaminated with flood water or sewage. Children's hands should be washed frequently, and children should not be allowed to play in previously flooded areas.

  • Conduct needs assessment to determine the status of public health infrastructure, utilities (e.g., water, sewage, electricity), and health, medical, and pharmaceutical needs.

  • Conduct surveillance of drinking water sources, injuries, increases in vector populations, and endemic, water-borne, and vector vector-borne disease.

  • Organize delivery of health care services and supplies and continuity of care.

  • Educate public regarding proper sanitation and hygiene.

  • Educate public regarding proper clean up.


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