Difference between Hurricane and Tornado

Although, a hurricane and a tornado have a lot in common, they are two different calamities. Size, shape, power and speed are the important factors which differentiate a hurricane and a tornado. The time of the year and the places where they may occur are also different. Let's take a quick look at their characteristics.

Hurricane is a tropical disturbance and is formed on the ocean water in the warm tropical regions. The three initial stages which lead to the formation of a hurricane are: tropical depression, tropical storm and then the fierce hurricane. When the surface of water is warm enough, around 27 degrees Celsius, a tropical depression is formed on the ocean due to a storm. As the speed of the tropical depression exceeds 39 mph, it turns into a tropical storm. The tropical storm becomes a hurricane, if it reaches a speed of 75 mph.

A hurricane can be viewed as an engine that gets its energy from the moisture evaporated seawater and heat. The hurricane is a spiral wind pattern and the center of which is called the 'eye of the hurricane'. The diameter of the eye is around 10-20 miles. The center of the eye is calmer than the other regions of the spiral storm. Usually, a hurricane loses its power, as it approaches the coast. It brings in torrential rains and fierce winds and mostly coastal areas are affected due to hurricane.

A hurricane is known by different names, according to the places where it occurs. It is called hurricane, if it takes place in the Atlantic Ocean and northeast Pacific Ocean. A hurricane in the Indian Ocean, is known as a cyclone. The strength of a hurricane is measured on the Saffir-Simpson scale from 1 to 5.

A tornado, commonly known as twister, is usually formed on land and is a fierce spiral funnel-shaped storm. A tornado is formed, when a cold front meets warm front. Clouds are formed, when the cold air tries to lift the warm air. A funnel-like structure formed in the cloud or which appears to be hanging from the cloud is the eye of the tornado. The eye of the tornado is very fierce, and can take away everything that comes in its way, just like a vacuum cleaner. The speed of a tornado is greater than 100 mph. A tornado is classified, according to its intensity as weak, strong or violent, viz.:

Weak tornado: A weak tornado has a speed of less than 110 mph and can last for 1-10min. 69% of tornadoes are weak.
Strong tornado: This type of tornado is strong with a speed varying from 110mph to 205 mph and can last for 20 min. 29% of tornadoes are strong.
Violent tornado: A violent tornado occurs rarely and only 2% of these are fiercely violent. This type of tornado has a speed greater than 200 mph and can last for about an hour.

Central North America is where tornadoes occur frequently; and therefore the area is called the 'tornado alley'. It is observed that a tornado usually starts on agricultural fields. Change in climate, is often witnessed in agricultural areas, which is a favorable condition for an outset of a tornado. Europe and Southeast Asia, also witness the formation of a tornado.

The hurricane as well as the tornado are an outcome of thunderstorms, but have certain differences.

• A hurricane is born on water; while a tornado is born on land.
• The eye of a tornado is only a few feet in diameter, while the diameter of hurricane's eye extends to 10-20 miles.
• The eye of a hurricane is less chaotic and is calmer than the violent eye of a tornado.
• The tornado last for few minutes and hurricane can last for two-four weeks.
• A tornado occurs from April to June while a hurricane occurs in the months from June to November.
• A hurricane is larger in size and many a time, produces a number of tornadoes.
• The hurricane is long-lasting, but the tornado is more erratic and devastating in nature.
• Hurricane travels from east to west and a tornado travels from south-west to north-east.

There are many similarities in these frightening and devastating calamities. Both, the hurricane and the tornado circulate in counter-clockwise direction. Even if, there are specific seasons in which they most frequently occur, isolated events have been witnessed in any month of the year. Last but not the least, the destructive effects of both, like flash floods, mudslides and loss of life, are the same.