Tornado Impact Data: Visualizations by Andrea S. Johnson
Tornado Severity
The National Weather Service classifies the severity of a tornado using the F Scale. Dr. T. Theodore Fujita developed the damage scale to relate the degree of damage to the intensity of the wind [F0-F5].
The Enhanced F scale was adopted in 2007 and classifies damage as calibrated by engineers and meteorologists based on the most intense damage within the path [EF0-EF5].
Questions Answered
- What are the most common severity measurements of tornado events?
- How are the frequency of tornado events and the measurements of impact related for each severity measurement?
- Does an F5 event do more damage than a large number of F1 events?
Conclusions:
This plot shows that the counts, or frequency, of tornado events decline significantly as the severity measures increase. The remaining measurements of impact are based on the average annual impact for ALL tornado events of that severity. In other words, average annual fatalities for all combined EF0 events are significantly lower than for all EF5 events.
The average annual impact for all combined EF3 events is slightly more than for all EF5 events. Despite the rare occurance of EF5 events, the impact of a single event is dramatic.