
312 ◾ The Security Risk Assessment Handbook
© 2011 by Taylor & Francis Group, LLC
100 years), high (40–60 hurricanes in 100 years), and moderate (20–40 hurricanes in
100 years) occurrence of hurricanes based on observations from 1888 to 1988.
8.1.9 Tornadoes
e incidence of tornadoes is concentrated along “tornado alley,” but they also
occur frequently in other areas in the eastern United States. e map in Figure8.13
shows areas of highest (probability of a tornado occurring in a single point is equal
to 1 in 2000 years) and high (probability of a tornado occurring in a single point is
equal to 1 in 5000 years) risk based on observations from ...