The Enhanced Fujita Scale is used by weather experts to rank tornadoes based on estimated wind speeds and related damage.
The rankings range from EF0 to EF5, which indicates wind speeds over 200 MPH.
The EF Scale, which became operational in 2007, is a revised version of the original Fujita Scale, and assesses damage based on how modern structures are designed.
The original system was developed by Dr. T. Theodore Fujita at the University of Chicago in 1970. According to NOAA, assessors use 28 "indicators" to estimate wind speeds, like damage to homes, barns, and trees. From there, each indicator gets scored based on the degree of damage, or DOD.