Impact of Weather on Health

Gib Parrish
Center of Disease Control
Atlanta, GA


The adverse impact (mortality and morbidity) of certain types of weather events on health is significant, and considerable effort is directed at reducing this impact. In these efforts, it is important to have a good understanding of the number of people affected by each weather event and the ways in which each event produces its adverse effects. Such understanding is crucial to the implementation of measures to prevent adverse effects from similar weather events in the future. Table 1 shows deaths from weather events and earth movements in the U.S. 1979-94.

Lack of Common Definitions

To determine the number of people affected by a weather event, one must decide which deaths, injuries, and illnesses should be counted and be aware of good sources of information on health affects. At present, there is no generally accepted definition of what constitutes a weather-related death, injury, or illness. Furthermore, those attempting to assess the impact of weather events may use different sources of information. As a result, it may be difficult to compare the impacts of different weather events on mortality and morbidity, and different groups may report dissimilar numbers of persons affected by the same weather event.


Each of the following scenarios presents a death that occurred at the time of or shortly after a weather event. Even among medical examiners, who are usually responsible for investigating and determining the cause of deaths due to injuries and violence and who were asked to review these scenarios at a recent meeting, there is often disagreement on what constitutes a "disaster-related" death. Mortality data from several eastern U.S. cities affected by the 1993 heat wave reinforce this point.

  1. Roof trusses from a neighbor's home were blown off during a hurricane, penetrating the roof of the decedent's home, striking her in the head. She died from blunt head injury.

  2. During a hurricane, a 72 year old man with a history of heart disease was in his garage lifting a piece of plywood to repair a storm-damaged window, when he collapsed and died immediately. Cause of death was cardiac dysrhythmia.

  3. Two days after a flood, a family was still without power. Because the decedent was afraid of the dark, her mother left a candle burning in her bedroom. During the night, the candle fell over and started a fire. The decedent died from carbon monoxide poisoning.

  4. 15 days after a tornado occurred, a workman was asphyxiated when a storm-felled tree trunk toppled back over, trapping him beneath its roots.

  5. The decedent - armed and apparently intent on looting a storm-damaged home - approached, shot at, but missed a homeowner; but the homeowner, defending his property, and himself, shot the would-be robber in the head.

  6. A husband shot and killed his wife and then himself 6 months after a hurricane; they were still living in temporary housing and their marriage had become unstable.

  7. The decedent was from another state. He was in the area providing relief efforts to victims who were displaced by a flood when he was stung by a hornet and died from anaphylactic shock. The decedent had no known history of allergies or previous exposure to stinging insects.

Relationship of death to disaster in seven scenarios, as judged by medical examiners at the annual meeting of the National Association of Medical Examiners, Charleston, South Carolina, 1994.

Death related to disaster? If yes, directly or indirectly?

Scenario Yes-Directly Yes-Indirectly Possibly No Total
1 63 0 0 0 63
2 4 43 4 12 63
3 5 41 9 8 63
4 27 30 4 2 63
5 2 13 6 41 62
6 0 10 15 37 62
7 1 9 7 46 63

Proposed Definition

To determine whether a death, injury, or illness is related to a weather event, the health effect must be temporally and geographically related to the weather event, and make causal and biological sense. Thus, in counting people affected by weather, one must establish reasonable geographic and time frames, and assess the nature of the circumstances and health effects:

Source of Information



The Public Health Consequences of Disasters, edited by Eric K. Noji, Oxford University Press, New York, 1997.

Societal Aspects of Weather

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