Fujita Scale

Fujita Scale, or F-Scale, levels are based on the damage caused by tornado wind speed. Dr. T. Theodore Fujita developed the scale in the early 1970s. Experts caution that the F-Scale is not a completely reliable measure, due to difficulties in precisely judging wind speeds.

Engineers and meteorologists have recently come up with a more accurate way to assess tornado damage called the Enhanced F-Scale. The new scale was put into effect February 7, 2007. In the Enhanced F-scale, there are customized standards for the different types of structures damaged in the tornado's path. As with the original F-scale, the enhanced version will rate the tornado as a whole based on most intense damage within the path. When determining the EF-rating, the EF-scale begins with the 28 Damage Indicators. Each of these indicators has a brief description of the typical structure for that category. They decided when assessing damage that it was important to continue to support and maintain the original F-scale, but that surveys should include additional data not used before, such as:

• Mean and maximum damage path width
• Basis for damage assignment
• Latitude/longitude of where the path began and ended
• Number of hours spent on the damage survey
• Names of survey team member(s)

Enhanced F Scale Wind Speeds

Enhanced F Scale Damage Indicators

See also: the Saffir-Simpson scale