An Improved Estimate of Tornado Occurrence in the Central Plains of the United States

Abstract

Tornadoes are a rare event, with the period of reliable record-keeping for many locations small compared to the likelihood of occurrence. The total number of recorded tornadoes varies a great deal from year to year. However, the number of recorded tornadoes has steadily increased. The cause of the variability includes climate, remoteness of an event from populations centers and dectection equipment such as radars, lack of reports, and incorrect reports. It is found that there is a positive correlation with observed occurrence and population density and radar locations. This paper seeks to remove the temporal variability and the biases in space due to the underreporting of tornado occurrence in a midwestern region. The resulting probability density function suggests an approximately 60% increase in the total likely number of tornado occurrence for a given year, as reflected in the increase in the average spatial probability density function.