Although we have advanced so much in the fields of science and technology, in the face of natural disasters like tornadoes and hurricanes, we are still helpless. Both tornadoes and hurricanes are wind-driven disasters that can wreak havoc on our lives and property.
But can you tell exactly how these disasters are different from one another?
As we’ve just mentioned, both tornadoes and hurricanes are characterized by strong horizontal winds, but that’s where the similarities between them end. While tornadoes originate on land, hurricanes originate in water bodies. In terms of size, hurricanes are much larger than tornadoes, with a diameter over 300-400 times that of the latter. Hurricanes have half the wind speed of tornadoes but can last for much longer (about a couple of weeks). Lastly, while tornadoes occur over 1000 times in the US every year, hurricanes occur only 10-15 times globally.
In this article, we aim to explore the differences that distinguish tornadoes and hurricanes on various grounds, such as their formation, speed, strength, and more.
Tornado Vs. Hurricane: at a glance
Before we begin to discuss the differences between tornadoes and hurricanes elaborately, let’s take a quick look at the basic characteristics of these disasters in the table given below:
|Shape||Tornadoes are shaped like a funnel, with a wide top growing narrower towards the bottom. This shape is also referred to as a “vortex”.||Hurricanes are circular in shape and possess a well-defined center. The winds are light in the center but increase rapidly as they move towards the edge.|
|Place of origin||Land||Water|
|Wind speed||Average wind speed ranges between 160-200 mph, but can also cross 300 mph in severe cases.||Wind speed doesn’t cross 180 mph.|
|Size (diameter)||Less than half a mile.||Extends up to 200-300 miles on average.|
|Other characteristics||· Strong cyclonic winds
· Large hail
· Heavy rainfall
· Clouds to ground lightning
|· Heavy winds (squall)
· Heavy rainfall
· Storm surge
|Forms of precipitation||Sleet, rain, and hail||Rain|
|Rotation||Northern hemisphere: counter-clockwise
Southern hemisphere: clockwise
|Northern hemisphere: counter-clockwise
Southern hemisphere: clockwise
|Most-affected locations||In the midwestern parts of the United States, where the convergence of the cold, as well as warm fronts, are common.||The Caribbean Sea|
|Lifespan||Tornadoes don’t usually last for longer than an hour.||Hurricanes can last for 2-3 weeks at times.|
|Occurrences per year||Can occur anywhere between 800-1200 times in the United States.||Usually occurs about 10-15 times worldwide.|
|Advanced warning||Weather forecasts can usually warn about a tornado only 10-15 minutes prior to it.||The area where a hurricane is about to hit can be predicted about 4-7 days beforehand by the weather forecasters.|
How are tornadoes formed?
Before looking into its formation, let us first understand what tornadoes really are.
A tornado is a vigorously rotating column of air that is in contact with both the ground and a cumulonimbus cloud.
Although tornadoes come in all shapes and sizes, they are mostly seen in the form of a condensation funnel, stemming from the base of a cumulonimbus cloud. Due to the speed of wind rotation inside it, there is always a swirling cloud of dirt and debris at the tornado’s foot.
Now, let’s get to the formation part.
The first step in the formation of a tornado is the heating of the air near ground level. Localized pockets of air start becoming warmer than their surroundings and begin to rise. In this way, the cumulus clouds are formed, which keep growing until they turn into a storm (cumulonimbus) cloud.
When the cloud forming procedure occurs in an atmosphere where the wind speed increases sharply with the height (strong vertical wind shear), the thunderstorm updraught might begin rotating.
The strong updraught then tilts this rolling motion into a vertical position, making the spin occur in a vertical axis, not quite unlike the motion of a merry-go-round.
Thunderstorms that exhibit persistent and deep rotation are known as Supercells.
The downdraughts within the storm help in concentrating the rotation and bringing it down to the lower levels. Ultimately, the rotation of the storm becomes so strongly and completely focused that a narrow, vertical column of vigorously rotating air is formed.
If this column of air reaches the ground, a tornado is born. It is almost always visible due to the formation of the condensation funnel, which is formed due to the reduced pressure within the tornado vortex. A small cloud of dust and debris swirling at the foot of the tornado also helps in making the tornado visible.
After some time, cold downdraughts envelop the tornado, effectively cutting off the supply of warm air. The tornado starts narrowing down by this time, and eventually, the vortex dissipates.
Different types of tornadoes
Named after their thin, almost rope-like appearance, the rope tornadoes are the smallest of all tornadoes.
Although all the tornadoes begin their cycle as a rope tornado and then grow larger, the rope tornadoes dissipate into thin air beforehand. Due to this, these tornados usually last for the shortest period of time.
Just like the rope tornadoes, the cone tornadoes are also named after their cone-like appearance. These tornadoes have a wide opening where they meet the thunderstorms and get narrower as they move down to the ground.
Of all the tornado types we’ve mentioned above, wedge tornadoes are the most dangerous. These tornadoes have the longest diameter of the three and, therefore, seem to have more width than height.
Almost all of the highly destructive tornadoes in history have been wedge tornadoes.
Multiple Vortex Tornado
As the name itself suggests, a multiple vortex tornado occurs when more than one rotating air column is formed at the same place and time.
Under these circumstances, both the air columns start spinning around a single center meanwhile rotating on their individual axes. These tornados are very intense and cause heavy damage in the area.
How are hurricanes formed?
Before delving into how hurricanes are formed, let’s first understand what they are. Hurricanes are a type of tropical cyclone formed over either the eastern Pacific Ocean or the Atlantic Ocean.
Because all the tropical cyclones are formed the same way, regardless of their names, we will discuss how a tropical cyclone is formed in this section.
Now, let’s think of the tropical cyclone as a vast engine that runs on moist, warm air. It is because these cyclones use moist air as a fuel that they are always formed on the surface of the ocean. The air near the ocean surface is always warm, which is why it rises up, creating a low-pressure area below.
As the warm air rises up, the air from the surrounding areas pushes into this low-pressure area, eventually becoming warm and rising upwards. As this process is repeated, the air present in the surrounding areas keeps swirling into the low-pressure area.
Meanwhile, the warm air that has risen up cools down slowly as it moves away from the surface of the ocean. Upon cooling down, the vapor present in this air condenses and turns into clouds.
As the whole system of clouds and wind grows and swirls faster, an eye is created in its center. This eye has a very low-pressure area, while the air pressure surrounding is higher. This is how a storm is formed.
The difference between a storm, a tropical storm, and a tropical cyclone is based on its speed. As the storm crosses the speed of 39 mph, it is called a Tropical Storm. And when the tropical storm reaches the speed of 73 mph, it is officially considered Tropical Cyclone or a Hurricane.
Differences in location
We’ve already established that tornadoes and hurricanes have different points of origin. While tornadoes are formed on land, hurricanes form over warm waters.
In this section, we will take a closer look at when and where do these disasters occur.
Where do tornadoes occur?
As we’ve learned above, thunderstorms are vital in the formation of tornadoes, which means that tornadoes are most likely to occur in areas that have ideal conditions for thunderstorms. The Great Plains in the central United States are, thus, the most suitable location for tornadoes.
The warm air traveling north from the Gulf of Mexico meets the cold air traveling south from Canada in these plains, causing storms. Because of it, the area is now referred to as the Tornado Valley.
While tornadoes can occur in the United States all year long, they mostly form in the spring and summer seasons, making May and June the peak tornado months.
Where do hurricanes occur?
If you’ve gone through the last section carefully, you might have noticed that hurricanes need a large source of warm waters for their formation. This is why they can only occur in the large basins of the world. Some of these cyclones are more active than others.
The hotspot of hurricanes lies in the Atlantic Basin, which includes the eastern and central North Pacific Ocean, the Gulf of Mexico, the Atlantic Ocean, and the Caribbean Sea.
According to the National Oceanic and Atmospheric Administration (NOAA), most hurricanes occur between June 1st and November 30th, which is why this period is referred to as the Hurricane season. However, in some rare cases, hurricanes have occurred outside of the season as well.
Differences in intensity
Since we’ve already established that tornadoes and hurricanes are two different phenomena, it is obvious that they would have different strengths and intensities as well. But if we compare the two, which disaster will trump the other?
Well, before we get into it, let’s learn a little about how the strength of these disasters is measured.
How to determine the strength of a tornado?
The strength of a tornado was earlier measured using the Fujita Scale invented in 2007. However, the scale we use to determine a tornado’s strength is a modified version of the same scale, known as the Enhanced Fujita Scale.
This scale rates the tornado’s strength between 0-5. Take a look at how the scale works in the table given below:
|Types of damage|
|EF-0||65-85 mph||Some roofs could be peeled off; shallow-rooted trees could get pushed over; minor damage to sidings and gutters.|
|EF-1||86-110 mph||A considerable amount of stripped roofs; severe damage to mobile homes; broken doors, windows, and other glasses.|
|EF-2||111-135 mph||Roofs of the well-constructed houses could be ripped off; home foundations shifted; cars lifted off ground; large trees uprooted.|
|EF-3||136-165 mph||Large constructions like multi-storeyed buildings and malls were damaged; heavy automobiles lifted off ground, trains overturned.|
|EF-4||166-200 mph||Most well-constructed houses and structured completely leveled; cars were thrown far away; small missiles generated.|
|EF-5||more than 200 mph||Structural deformation in high-rise buildings; houses and automobiles lifted off ground and swept away; larger missiles flying through the air.|
How to determine the strength of a hurricane?
The strength of a hurricane can be determined by the damage it does to any property befalling its path. The Saffir-Simpson Hurricane Wind Scale was devised to make this determination easier on us.
This scale gives the hurricane a rating between 1 and 5 based on the potential property damage. Out of these five categories, the last three are considered major as they can lead to a significant loss of life and property
|Types of damage|
|1||74-95 mph||Possibility of damage to the shingles, gutters, and sidings of well-framed houses; tree branches snapped.|
|2||96-110 mph||Minor damages to the roofing and siding of well-built houses; shallow-rooted trees uprooted.|
|3 (major)||111-129 mph||Severe damage to the walls and roofing of well-framed houses; roadblocks caused due to uprooted trees; expectation of near-total power outage.|
|4 (major)||130-156 mph||Loss of exterior walls and roof structures in well-framed houses; power poles downed and trees uprooted; no power or electricity for days, unless the cyclone passes.|
|5 (major)||157 mph and higher||Destruction of well-framed houses, total wall collapse, and roof failure; power outage for weeks; area uninhabitable for months.|
In this article, we have learned that although tornadoes and hurricanes are both air-powered natural disasters, both of them are very different from each other. While tornadoes originate on land, hurricanes are formed on large water bodies. The wind speed in tornadoes is significantly faster than the wind speed of the hurricane.
However, while tornadoes usually last for minutes, a hurricane, once formed, can last for days, even weeks at times.