What are Hurricanes, how severe is Hurricane Laura, how are Hurricanes formed and named?

Due to Hurricane Laura, at least 14 people died in the southern US states of Louisiana and Texas. Ten victims were in Louisiana and four in Texas. It left a trail of destruction in Louisiana and Texas. Winds up to 150mph (240km/h) caused severe damage and lead to power cuts to more than half a million homes and a chemical fire from an industrial plant.

According to Mr Edwards “Hurricane Laura is the fifth strongest storm to make landfall in the United States in recorded history and the first in memory to maintain major hurricane strength because it travelled through Louisiana, bringing catastrophic destruction to several parishes.”

About Hurricane Laura

It is a Category 4 storm that made landfall in southwestern Louisiana on 27 August, 2020. As discussed above the wind speeds reached up to 150mph (240km/h) and is one of the most powerful storms to hit the state.

What are Hurricanes?

They are large, swirling storms and produce winds of 119 km/h or 74 mph or higher. The winds are faster than a cheetah which is the fastest animal on land. Also, winds from a hurricane can damage buildings and trees. They form over warm ocean waters. Sometimes they strike on lands also. But when a hurricane reaches on land, it pushes a wall of ocean water ashore. This wall of water is known as a storm surge. These heavy rain and storm surge from a hurricane can cause flooding.

After the formation of a hurricane, the weather forecaster predicts its path. Further, they predict how strong it will get. With this information, people get the time and become ready for the storm.

Types of Hurricanes

Hurricanes are of five types or hurricanes are categorised into five. The scale of categories is known as the Staff-Simpson Hurricane scale. On wind speed, the categories are based.

Category 1: Winds 119-153 km/hr (74-95 mph) that is faster than a cheetah.

Category 2: Winds 154-177 km/hr (96-110 mph). They are as fast or faster than a baseball pitcher’s fastball.

Category 3: Winds 178-208 km/hr (111-129 mph). They are similar, or close, to the serving speed of many professional tennis players.

Category 4: Winds 209-251 km/hr (130-156 mph). They are faster than the world’s fastest rollercoaster.

Category 5: Winds more than 252 km/hr (157 mph). They are similar, or close, to the speed of some high-speed trains.

Daily Gist of ‘The Hindu’, ‘PIB’, ‘Indian Express’ and Other Newspapers: 28 August, 2020

Several parts of Hurricane are as follows:

Eye: It is the ‘hole’ at the center of the storm. In this area, winds are light and skies are partly cloudy, sometimes even clear.
Eye wall: It is a ring of thunderstorms. These storms swirl around the eye. The winds are strongest and rain is heaviest in the wall.
Rain bands: Band of clouds and when rains go far from a hurricane’s eye wall. These bands stretch for hundreds of miles and contain thunderstorms and sometimes tornadoes.

How are hurricanes formed?

Hurricanes or tropical cyclones use the warm or moist air like fuel and form over warm ocean waters near the equator. According to NASA, when the warm or moist air rises upward from the surface of the ocean, it forms an area of low air pressure below. After this, the area from the surrounding areas rushes to fill this place and eventually rises when it becomes warm and moist too.

Now, what happens when warm air rises: When it rises and cools off, clouds are formed due to the moisture. This system of clouds and winds continues to grow and spin. It is fuelled by the heat of the ocean and the water that evaporates from its surface.

When storms systems rotate faster and faster, an eye in the centre forms. When storms form towards the north of the equator it rotates counter-clockwise and those form to the south spin clockwise due to the rotation of the Earth.

When Storm become a Hurricane?

As a tropical disturbance hurricane starts out. This is an area that is formed over warm ocean waters where rain clouds are building. Sometimes a tropical disturbance grows into a tropical depression. This area is of rotating thunderstorms with winds of 62 km/hr or 38 mph or less.

If winds reach 63 km/hr (39 mph), a tropical depression becomes a tropical storm.

If winds reach 119 km/hr (74 mph), a tropical storm becomes a hurricane.

Why and how are Hurricanes named?

At one time, there can be more than one hurricane. That is why hurricanes are named as names make it easier to keep track of and talk about storms. When the storm becomes a tropical storm it is given a name. That name stays with the storm if it goes on to become a hurricane.

Note: Tropical disturbances and depressions don’t have names.

Every year in alphabetical order, tropical storms are named. The names come from the list of names for that year. There are six lists of names. Every six years, lists are reused. If a storm does tons of injury or damages a lot, its name is sometimes taken off the list. It is then replaced by a new name that starts with the same letter.

Hurricane topic is important for exam perspective also as it can be asked in GS Paper 1.

Daily Gist of ‘The Hindu’, ‘PIB’, ‘Indian Express’ and Other Newspapers: 29 August, 2020

IAS Prelims Mock-Test 2020 – Set 5, 28 August