Understanding the EF-Scale: The Official Tornado Ranking System
The EF-Scale is the official tornado ranking scale of the U.S., Canada, and more countries. Learn more bout it here…
The EF-Scale is for tornadoes to rate them on a scale from 0 to 5 (and more). The EF-Scale categorized tornadoes as the Saffir-Simpson scale categorizes hurricanes. It is used for most tornadoes world-wide to assess how strong the tornado was based on a few factors. In recent years, the scale has faced criticism about if it is precise and if the NWS should update it. In this post, discover the unknown 7th tornado ranking. Find out why some think the scale is outdated. Learn more interesting facts in this post.
This post is all about the EF-Scale.
The Controversial EF-Scale
The Fujita Scale
The first section of this post will be about the original Fujita scale. The F-scale ran from F0-5, even though Ted Fujita created ratings all the way to 12. These were not used because it would be impossible to tell from the damage of the structures. Homes can’t even withstand the winds of an F4 or F5 tornado. The wind speeds of the F-Scale is different from the EF Scale today. That is why it was updated because these wind estimates were found wrong. Here is the F-Scale wind estimates…
- F0: 40-72
- F1: 73-112
- F2: 113-157
- F3: 158-206
- F4: 207-260
- F5: 261-318
What is the EF Scale?
The Enhanced Fujita Scale is a 7-point scale, with tornadoes almost always ranging from EF0 to EF5. The scale starts at EF0 with estimated wind speeds ranging from 65-85 mph. This damage is usually weak like snapping power poles, damaging shingles, moving cars, and destroying mobile homes. The scale then moves to EF1, with large trees completely uprooted and collapsing weak walls. EF2 tornadoes flip heavy cars, knock over brick walls, and tear roofs off homes.
This is where tornadoes are labeled as intense. EF3 tornadoes knock over exterior walls of houses, toss cars mild distances, and throw heavy objects high into the air. Violent tornadoes start at EF4. These monsters sweep most homes clean. They mangle and toss cars large distances and leave whole blocks devastated. High-end EF4s are often indistinguishable from EF5 damage to the naked eye. This similarity has caused a lot of controversy over the years. The scale ends at EF5, with extreme damage with the top built houses being completely swept away.
There is also a rating that is rarely used each year. It is EFU. A tornado can be rated as an EFU because it didn’t hit anything so we can’t estimate the wind speeds. This happens if it stays over an open field.
How is a Tornado Categorized?
Scientists categorize a tornado by the damage it causes. They don’t look at recorded wind speeds that the vortex created. They do that because it’s fairly rare to get wind speeds recorded from inside a tornado. Instead, they assess the tornado damage. There are 28 damage indicators on the scale to look at what wind speeds have caused the damage it caused. They so this based on off of how severe the tornado destruction was. These indicators range from different types of trees, to two story homes, to high rise buildings.
This type of damage rating system has caused a lot of debate over the years. Questions arise if some indicators are too low. There is also debate if factors like recorded wind speeds should be factored in, too. Some tornadoes have had recorded wind speeds above their damage rating since they didn’t hit anything at peak strength. For example, the 2013 El Reno tornado had recorded windspeeds over 300 mph. It also had a record-breaking width, but only got an EF3 rating.
Enhanced Fujita Scale Controversy
There is a lot of controversy over the EF Scale for various reasons. This section discusses these reasons. This topic really deserves its own long post. We will probably deal with it later. For now, this will cover the tip of the iceberg. This controversy arises from how a tornado is rated. The debate focuses on whether this tornado should’ve been ranked higher due to the rating system. Here is a list of things that have been brought up to add, remove, or change about the rating process…
- Add Ground Scouring (ground being heaved from the Earth like grass and mud)
- Add Recorded Wind Speeds by Doppler Radar
- Remove Factor of Debris Hitting Buildings
- Add Vehicles as Damage Indicators
Some examples of tornadoes that have been brought up in this controversy include…
- 2016 Rochelle, IL
- 2013 El Reno, OK
- 2014 Vilonia, AR
- 2023 Matador, TX
- and many more…
Some scientists are working on a new scale. They are doing this because of these reasons. Nevertheless, we don’t know if it will be finished. We also don’t know if it will be put into place. This section provided only a very brief overview of the controversy. To learn about it in depth, there are great documentaries on platforms like YouTube.
