You may think the EF rating (EF0 through EF5) indicates the size of a tornado. If so, you’d be wrong.
Meet Dr. Fujita
Dr. Tetsuya Theodore Fujita (Oct. 23, 1920 – Nov. 19, 1998) was a Japanese-American meteorologist at the University of Chicago. His studies revolutionized our knowledge of
severe thunderstorms, tornadoes and hurricanes.
He is best known for creating the Fujita scale of tornado intensity, used for more than thirty years, based on his studies of wind speed and storm damage. The original F scale ratings were estimates, based partly on the 1805 Beaufort Wind Scale.
The original F scale has been replaced by the Enhanced Fujita (EF) scale as the standard for assessing tornado damage. Developed by engineers and meteorologists, it rates tornadoes as class EF0 through EF5 based upon 8 possible damage levels and 28 different types of indicators (trees, houses, outbuildings, power poles, signs, etc.)
TV meteorologists may report an EF rating of a tornado based on radar, but the official EF rating can’t be confirmed until a team from NOAA has time to inspect and analyze the damage left in the storm track.
EF0: 65 – 85 MPH Gusts
At the lowest EF rating, you can expect to find damage to signs, shallow-rooted trees, tree branches, and unsecured outdoor items. By comparison, a Category 1 hurricane has wind speeds of 74 to 95 mph.
EF1: 86 – 110 MPH Gusts
An EF1 tornado can push cars and trucks off the road, knock over mobile homes, and tear roofs off of some frame houses. Wind-borne debris starts to become dangerous.
EF2: 111 – 135 MPH Gusts
At EF2, a tornado can rip roofs from many houses, demolish mobile homes, and push over fully loaded trucks and railroad boxcars. Even light debris can become deadly wind-driven missiles.
EF3: 136 – 165 MPH Gusts
At this speed, cars can be picked up and thrown. Even well-built homes will suffer catastrophic damage. Most trees will be uprooted or severely damaged. Railroad trains will be toppled. Flying debris can cause significant secondary damage.
EF4: 166 – 200 MPH Gusts
An EF4 tornado will destroy most residential and shopping structures. Cars can be thrown quite a distance. Some structures will be picked up and thrown. Nearly any wind-borne object becomes deadly.
EF5: Over 200 MPH Gusts
All but the strongest buildings are destroyed. Even large commercial structures (office buildings, hospitals) may be damaged beyond repair. Bark is stripped off of trees. Pavement can be sucked up from the ground.
A Real-Life Example
On May 3, 1999, an F5 tornado with wind speeds of 300 mph (measured by radar) tore through towns and suburbs southwest of Oklahoma City. Within the storm track, the following damages were found:
- Many trees were de-limbed and debarked
- Thousands of homes were destroyed
- Dozens of homes disappeared, leaving only concrete slabs
- Entire apartment buildings were demolished, leaving only the foundations
- Asphalt pavement was stripped from the ground, leaving bare dirt
- New cars were picked up and tossed a quarter mile (across I-40 in Del City)
Make Sure You Have a Plan
All but the weakest tornados are life-threatening. You will have very little time to take shelter. Make sure you have a plan before the storm happens.
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