If you’ve ever watched the movie “Twister” (1996), you’ve probably heard of tornadoes described as an F1, F2, etc. However, when tornadoes are on the ground, it wouldn’t be accurate to call them an F1 or an F2.

Tornadoes are rated based on damage. After a tornado passes through an area, the National Weather Service will survey the damage and rate the tornado based on the Fujita Scale. The Fujita Scale was developed in the early 70s, and each category F0 – F5 is assigned to a different level of damage. Each category is also given an estimate of the wind speeds that occurred in the tornado.

In 2007 the scale was adjusted to provide more accurate estimated wind speeds and it is now called the Enhanced Fujita Scale.

Below are examples of tornado destruction which have all been rated based on the Fujita Scale.

1. EF0, Estimated Wind Speeds 65 – 85 mph

2. EF1, Estimated Wind Speeds 86 – 110 mph

EF0 and EF1 tornadoes are the weakest and most common. They usually last under 10 minutes and cause 5 percent of tornado deaths.

3. EF2, Estimated Wind Speeds 111 – 135 mph

4. EF3, Estimated Wind Speeds 136 – 165 mph

EF2 and EF3 tornadoes can last over 20 minutes and account for 30% of tornado fatalities.

5. EF4, Estimated Wind Speeds 166 – 200 mph

6. EF5 Estimated Wind Speeds Over 200 mph

Only 2 percent of tornadoes are an EF4 or EF5. They account for 65 percent of tornado deaths.

Until Next Time,

Meteorologist Andrew Thut