Types of Disasters and Their Consequences

American Public Health Association 

In This Article


Tornados are rapidly whirling, funnel-shaped air spirals that emerge from a violent thunderstorm and reach the ground. Tornados can have a wind velocity of up to 200 miles per hour and generate sufficient force to destroy even massive buildings. The average circumference of a tornado is a few hundred meters, and it is usually exhausted before it has travelled as far as 20 kilometers (12.4274 miles). Severity is rated on the Fujita Scale according to wind speed. The Fujita Scale uses a scoring system of F0 (no damage) to F5 (total destruction). The extent of damage depends on updrafts within the tornado funnel, the tornado's atmospheric pressure (which is often lower than the surrounding barometric pressure), and the effects of flying debris.

Approximately 1,000 tornadoes occur annually in the United States, and none of the lower 48 states is immune. Certain geographic areas are at greater risk due to their recurrent weather patterns; tornados most frequently occur in the midwestern and southeastern states. Although tornadoes often develop in the late afternoon and more often from March through May, they can arise at any hour of the day and during any month of the year.

Injuries from tornados occur due to flying debris or people being thrown by the high winds (i.e., head injuries, soft tissue injury, secondary wound infection). Stress-related disorders are more common, as is disease related to loss of utilities, potable water, or shelter.

Because tornadoes can occur so quickly, communities should develop redundant warning systems (e.g., media alerts and automated telephone warnings), establish protective shelter to reduce tornado-related injuries, and practice tornado-shelter drills. In the event of a tornado, the residents should take shelter in a basement if possible, away from windows, while protecting their heads. Special outreach should be made to people with special needs who can make a list of their limitations, capabilities, and medications and have ready an emergency box of needed supplies. People with special needs should have a "buddy" who has a copy of the list and who knows of the emergency box.

Other precautions include those listed under Cyclone.

  • Work with emergency management on tornado shelter drills for vulnerable communities.

  • Conduct needs assessment using maps that detail pre-existing neighborhoods, including landmarks, and aerial reconnaissance.

  • Ensure the provision of medical care, shelter, food, and water.

  • Establish environmental controls.

  • Establish a surveillance system based at both clinical sites and shelters.


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