(January 2011) Mortality remains one of the major outcomes related to natural disasters, and a recent study on which types of disasters are the deadliest has yielded interesting results.

University of South Carolina researchers Kevin Borden and Susan Cutter found that, surprisingly, heat or drought to be the deadliest natural hazard during the time period from 1970 to 2004, followed closely by severe summer weather such as thunderstorms, wind, and hail (see table). Together, these two types of disasters accounted for more than one in three deaths over the period. Winter weather accounted for another one-sixth of deaths. By contrast, hurricanes, wildfires, and geophysical events such as earthquakes (all of which are among the more destructive hazards in terms of property damage) combined for just 5 percent of U.S. disaster-related deaths since 1970.


Deaths From Natural Disasters by Type, 1970-2004

  Number Percent
All Deaths From Natural Disasters 19,959 100.0
Heat or Drought 3,906 19.6
Severe Weather (severe storm/thunderstorm, fog, hail, wind) 3,762 18.8
Winter Weather 3,612 18.1
Flooding 2,788 14.0
Tornado 2,314 11.6
Lightning 2,261 11.3
Coastal (storm surge, rip current) 456 2.3
Hurricane or Tropical Storm 304 1.5
Geophysical (earthquake, tsunami, volcano) 302 1.5
Mass Movement (avalanche, landslide) 170 0.9
Wildfire 84 0.4

Source: Kevin A. Borden and Susan L. Cutter, "Spatial Patterns of Natural Hazards Mortality in the United States," International Journal of Health Geographics 7, no. 64 (2008): figure 1 and table 3, accessed at www.ij-healthgeographics.com/content/7/1/64, on Dec. 13, 2010. 


Frequency is a factor in how deadly an event is over such an extended time period. While a single heat wave might not be as catastrophic as a major hurricane, heat waves are more common, which means they ultimately can result in more deaths and injuries over several years.

Although the greatest number of deaths from a single disaster might occur in places with large populations, these are not necessarily the areas where individual residents are most likely to die from such an event in the United States. The areas with the greatest mortality risks are in the South Atlantic and Gulf coasts, the lower Mississippi River valley, the northern Great Plains, south-central and southwestern Texas, and the Rocky Mountain West. People living in urbanized areas, particularly in the Northeast, have the lowest mortality risk, mainly because the number of deaths from natural hazards is small relative to the large population size. According to the authors, identifying the areas most prone to disaster-related deaths could result in more resources for these areas aimed at prevention.


Kelvin Pollard is a senior demographer at the Population Reference Bureau.


Reference

Kevin A. Borden and Susan L. Cutter, "Spatial Patterns of Natural Hazards Mortality in the United States," International Journal of Health Geographics 7, no. 64 (2008), accessed at www.ij-healthgeographics.com/content/7/1/64, on Dec. 13, 2010. Borden and Cutter used data from the Spatial Hazard Event and Loss Database for the United States to examine mortality patterns between 1970 and 2004. The database includes events that caused at least $50,000 in damage or at least one death (regardless of the amount of damage).