Tornadoes are as devastating as they are fascinating. These whirling super storms inspired countless Hollywood hits such as Wizard of Oz and Twister. With their prevalence in the media, it’s clear the public has a fascination with tornadoes. But what do we really know about this awe-inspiring weather phenomenon? From Tornado Alley to the Fujita Scale, let’s break down 15 mind blowing facts about tornadoes.
There are Different Types
We’re accustomed to seeing the traditional funnel-shaped tornadoes that make contact with the ground for long periods of time. These are called supercell tornadoes. But did you know there are several other kinds?
- Landspout tornadoes – Weaker tornadoes often formed near the edge of the rain-cooled downdraft air from a thunderstorm.
- Gustnadoes – Weak and short-lived, they often form along the gust front of a thunderstorm.
- Waterspouts – Form over open water by weak thunderstorms and feature a funnel made of freshwater.
- Dust devils – Only lasting a few minutes, they form in deserts and dry lands because of heat from the sun and light winds.
- Firewhirls – Formed due to intense heat from wildfires and volcanic eruptions, these whirlwinds can carry smoke and fire.
Bigger Doesn’t Always Mean Stronger
You may assume thicker wedge-shaped tornadoes are more dangerous, but thinner tornadoes can also be quite powerful. Small, rope-like tornadoes can feature deceivingly high wind speeds, wreaking havoc on anything in their path. It’s also important to note that many tornadoes will change shape and size during their lifespan.
They Are Most Common in the US
The United States experiences over 1,200 tornadoes annually. That figure dwarfs the yearly rate of other countries around the world. For instance, Canada experiences roughly 300 annually, while the entire continent of Europe only experiences about 100 annually. Unfortunately for the US, certain areas of the country provide the perfect environment for this type of storm.
They Mostly Form in Tornado Alley
The area to blame for the unprecedented number of tornadoes in the US is Tornado Alley. It’s situated between the Midwestern and Southern US. While every state in the US reports tornado activity, Tornado Alley experiences a disproportionate number of tornadoes. This is primarily due to the interaction of cool, dry air from the north and warm, moist air from the Gulf of Mexico.
Some Cause Damage Without Touching the Ground
A tornado doesn’t even have to touch the ground to cause damage. The funnel itself doesn’t actually cause substantial damage, and as we discussed above, size doesn’t determine the severity of the storm. It’s actually the circular surface wind that violently tears apart anything in its wake. From a distance, the debris cloud may actually serve as a better indicator of how much damage the tornado is causing.
False Tornado Safety Rules Are Dangerous
It’s vital to know how to protect yourself if a tornado forms close to you. The lowest level of your home, preferably the basement, is the safest place you can be during the storm. Some people incorrectly say it’s safe to wait out a tornado in your car, but this is very wrong. You may have also heard that you can seek shelter under a highway overpass, but these can actually be more dangerous due to increased wind speeds. The rule of thumb is to stay as low as possible and avoid areas with lots of trees.
Tornadoes Can be Different Shapes
Tornadoes can manifest in a few different shapes. Their shape can vary based on type and the phase the storm is in. Here are the main shapes you can observe:
- Wedge – These wide funnels can grow so thick that they appear to be clouds.
- Dust Swirl – Weaker landspouts might appear as swirling dust that quickly dissipates before they even hit the ground.
- Dissipating – In this stage, the tornado may “rope out” into twisting, complex shapes.
- Shrouded – This type of tornado can be the most dangerous because it’s not actually visible. Its storm shrouds the circular surface wind that powers a tornado.
They Can Form “Debris Balls”
When tracking a tornado, experts will search for a “debris ball” on the weather radar. Also known as a tornadic debris signature (TDS), these small circular areas of high reflectivity can indicate a tornado is present. The signature suggests that there is significant debris suspended in the air because of strong winds.
Wind Speed Can Get Up to 300 MPH
On average, most tornadoes are less than 110 miles per hour (MPH). The range is roughly 65–110 MPH. On rare occasions, particularly destructive tornadoes can reach up to 300 MPH. The highest tornado wind speed ever recorded was 321 MPH. The storm occurred in Oklahoma City on May 3rd, 1999.
Spinning Direction Depends on Hemisphere
In the Northern Hemisphere, tornadoes normally spin counterclockwise while they spin clockwise in the Southern Hemisphere. When a tornado rotates in its normal direction, it is spinning cyclonically. This is because of a phenomenon called the Coriolis effect. This is the same force that controls the winds and ocean currents moving across Earth’s surface.
Sometimes, They Switch Directions
Due to the Coriolis effect, large storms always rotate cyclonically. But some smaller storms such as landspouts and gustnadoes aren’t beholden to the Coriolis effect. They can rotate anticyclonically, which means they spin opposite to their typical direction. This accounts for 1% of tornadoes.
Tornadoes Form Year-Round
Tornadoes can form in every season. The key conditions for a tornado are present year-round. These storms form when warm, moist air collides with cool, dry air, creating instability in the atmosphere. Spring is the peak window for tornadoes to form, but these factors are possible in the summer, fall, and winter too.
Ranked By the Enhanced Fujita Scale
The Enhanced Fujita Scale aids in ranking the strength of tornadoes in the United States and Canada. Introduced in 1971, the scale ranks the storms based on the damage they cause. The scale consists of six categories from zero to five. It factors in wind speed and damage to structures to categorize the strength of the storm.
“Tornado Outbreaks” Can Happen
During some particularly optimal weather conditions, an area can experience a “tornado outbreak.” This occurs when multiple tornadoes form from the same weather system in a short time period. These systems often form as a result of powerful jet streams, warm, moist air, and a cold front colliding. “Tornado outbreaks” can affect multiple states and regions.
