- Education and Science
Understanding the F-Scale for Classifying Tornadoes
April Showers Bring... Deadly Tornadoes
(I couldn't think of a decent rhyme.) Spring generally brings us the joy of the coming summer and an end to a cold winter, but sometimes along with it comes devastating and terrifying tornado filled storms that destroy everything in their path. Many lives have been lost and properties destroyed by these powerful and mysterious yet natural occurrences. Of course spring isn't the only time for tornadoes. Tornadoes can occur any time of year in any location, although in the United States they tend to favor spring and the middle of the country. According to the National Oceanic and Atmospheric Administration (NOAA), there are 800 tornadoes reported across the U.S., resulting in 80 deaths and over 1,500 injuries – www.nssl.noaa.gov/edu/safety/tornadoguide.html.
What is a Tornado Exactly?
For most of us the basic understanding of a tornado is a funnel cloud with fast moving wind produced during thunderstorms that you don't want to be in the path of. NOAA defines tornadoes as “A violently rotating column of air extending form a thunderstorm to the ground” - www.nssl.noaa.gov/edu/safety/tornadoguide.html. Tornadoes come in all different sizes and shapes including but not limited to white puffy looking things, water filled tornadoes called 'waterspouts', and debris filled monsters.
Most of us know that tornadoes are classified by an 'F'' scale, and that tornadoes in the F4 to F5 range are very destructive and dangerous. Most of us (Myself included) don't know what these 'F's stand for. My best guess would have been wrong and wildly inappropriate for this article.
The Original Fujita Scale
The 'F' is actually short for 'Fujita' after the man that helped create the scale. Ted Fujita along with Allen Pearson developed the original Fujita Scale and it became implemented as the standard scale for classifying tornadoes in 1971. The scale was used to retro classify many past tornadoes and any that came following its implementation until 2007. The scale classified tornadoes in a rating from 0 – 5 based on the damage they caused and providing an estimated wind speed. Because even today there is much that scientists and meteorologists still don't know about tornadoes and tracking the wind speeds within them, the system was never actually scientifically proven to be accurate. This isn't to say that it was a poor system and even though the classifications were based off the limited evidence present from a storm, these guesstimates provided a way to understand and classify the severity of tornadoes.
The Enhanced Fujita Scale
In 2007 the National Weather Service presented the new Enchanced Fujita Scale, which took the reins as the standard scale for classifying tornadoes. This scale is what is currently used today. While there still remains many mysteries regarding the actual wind speeds of tornadoes, this scale provides a much more accurate classification. It still uses the same F0 – F5 ratings of the original scale, but the result is derived from twenty eight damage characteristics. Using this many indicators of damage allows scientists and meteorologists to more accurately classify tornadoes.
This section is to cover a
simple understanding of how the classification system works.
F-0 tornadoes are the weakest tornadoes on the classification list. These small tornadoes usually don't get media coverage as they generally only cause minor damages to trees or houses such as guttering or shingles. The estimated wind speed of an F-0 is 65-85 mph.
F-1 tornadoes are considered to cause moderately more damage than the F-0 tornadoes including severe roof damages or busted windows. The estimated wind speed of an F-1 is 86-110 mph.
F-2 tornadoes can cause considerable damage including trees and cars being tossed around and severe damages to homes involving destroyed roofs or destroyed mobile homes. The estimated wind speed of an 111 – 135 mph.
F-3 tornadoes are where the real damages start. F-3 tornadoes can destroy houses and cause severe damage to even well built large structures. The estimated wind speed of an 136 – 165 mph.
F-4 tornadoes make up less than one percent of reported tornadoes. They are very dangerous and tend to cause massive amounts of damage. They can completely destroy well built house and buildings. The estimated wind speed of an 166 – 200 mph.
F-5 tornadoes are very rare. They destroy virtually everything in their path from houses to large concrete and steel reinforced buildings. F-5 tornadoes leave almost nothing standing. Approximately fifty tornadoes have been classified as F-5 tornadoes in the United States dating back to 1953. The estimated wind speed of an F-5 is anything over 200 mph.
I assume because F-5 tornadoes are so rare I was unable to find a picture of one though I am still looking. However, see the below picture of the damage caused by one.
- NOAA - National Oceanic and Atmospheric Administration
The National Oceanic and Atmospheric Administration (NOAA) is a federal agency focused on the condition of the oceans and the atmosphere. It plays several distinct roles within the Department of Commerce.
NOAA and the National Weather Service
Several times during the course of this article I have mentioned the National Oceanic and Atmospheric Administration (NOAA). This is because NOAA is the government agency that handles alerts, notifications, etc. about weather for the United States. The National Weather Service is a part of of NOAA. So in simple terms NOAA is likely the most reliable source for any information pertaining to weather.
On their webiste NOAA.gov you can find not only tons of information about weather, but you can also see all of the current warnings, watches, and advisories in effect across the entire United States.
Tornadoes can strike anywhere, and while scientists and meteorologists work constantly to find new ways to predict tornadoes they still can't predict exactly where and when tornadoes will strike. They can usually predict when an area has the right conditions for tornadoes. It is always wise to keep up with the current weather advisories in effect for your area and to have a plan in place just in case a tornado strikes near you.