Damage and death in historical tornadoes

NSSL scientists have been studying changes in deaths and damage from tornadoes in the United States occurring since the 19 th century. The research has focused on more than 100 tornadoes in order to identify the trends and possible future changes. When scientists adjust historical damage amounts for the total wealth of the United States in current dollars, they have found that there has been roughly $1 billion dollars of tornado damage per decade since 1890. The most damaging tornado in United States history was the violent tornado that struck Saint Louis, Missouri and East Saint Louis, Illinois on May 27, 1896. In current costs, it caused almost $3 billion in damage.

Death tolls from tornadoes have been steadily decreasing in the United States since 1925. Prior to that, the average number of deaths per year was about 1.8 per million population. This has now decreased to 0.12 deaths per million. The decrease has occurred because fewer tornadoes kill people now than previously and because the death toll in the deadliest tornadoes has decreased. An important cause of this trend has been the improvement in forecasts and warnings of tornadoes. Mobile homes still present a major challenge, however. The death rate for mobile home residents is approximately 20 times the rate for permanent home dwellers. Since the number of mobile home residents in the central and southeastern United States, where tornadoes are most frequent, more than tripled from 1970 to 1990, the fraction of all tornado deaths in mobile homes has increased from about 25% of all deaths 25 years ago to 50% of all deaths now.By Harold E. Brooks