Hurricane – All about the topic

Hurricanes are tropical cyclones with a speed of more than 118 km/h and are a widespread severe weather phenomenon that can often cause great destruction. In this explanation you can find out exactly where hurricanes occur and how they form.

Hurricane – simply explained

What exactly is a hurricane anyway? The word hurricane comes from the Indian language and can be translated as «god of the wind».

A hurricane is a tropical cyclone that originates in the Atlantic, North or South Pacific, or Caribbean.

The origin of a hurricane is not only limited locally, but the hurricane must also have a speed of at least 188 km/h. They always arise over the sea when a variety of factors interact. These factors are:

  • depression
  • Water temperature between 24°C and 28°C
  • Maximum water depth of 50 meters

The hurricane season lasts from early June to late November in the North Atlantic and North Pacific, and begins in mid-May in the North Pacific. Most hurricanes occur between July and September because the water can heat up sufficiently during these months.

How exactly a hurricane develops step by step, we will explain later in more detail.

Distinction between hurricane and cyclone & typhoon

Hurricanes are often confused with the terms cyclone and typhoon. All three are tropical cyclones, but what’s the exact difference?

The distinction between the three types of hurricane lies in the place of origin. Unlike hurricanes, cyclones occur in the Indian Ocean and South Pacific. The typhoon, on the other hand, originates in East and Southeast Asia and in the northwestern part of the Pacific.

Figure 1: Hurricane areas around the worldSource: Aktion-Deutschland-hilft.de

Hurricane Naming

Hurricane names are short and easy to remember. They are assigned by the World Meteorological Organization (WMO).

Since 1979, the storms no longer have only female names. In addition, names with the letters Q, U, X, Y and Z are generally not assigned.

The WMO creates several alphabetical lists with 21 first names each for the naming. Each list is used every six years. If more than 21 hurricanes occur in a year, the letters of the Greek alphabet are used as names from the 22nd hurricane.

So far, however, this was only the case in 2005, when a total of 28 hurricanes formed over the Atlantic. However, the names of hurricanes that were particularly devastating appear only once and are then removed from the list.

Structure of a hurricane

A hurricane is cylindrical. In the center is the eye, with a diameter of 15 to 30 km. Here it is almost completely windless and cloudless.

In the eye, there is a very low pressure directly above the sea surface, which sucks in air from all sides. This air is directed into a vortex around the eye. This vortex moves counterclockwise in the northern hemisphere and clockwise in the southern hemisphere. The lower the air pressure in the center, the stronger the storms circling around the center and the heavier the precipitation.

Figure 2: Structure of a hurricaneSource: dw.de

formation of a hurricane

There are three conditions that must be met for a hurricane to occur in the first place.

On the one hand, hurricanes only occur when the water temperature is at least 26 degrees Celsius. In rarer cases, a temperature between 24°C and 28°C is sufficient.

On the other hand, the area with the warm water must be large enough.

The third requirement is the prevalence of a low pressure area.

If these three factors are met, a hurricane can develop. This is how it works:

  1. First, due to the warmth of the sun, large amounts of warm water evaporate over the warmed ocean.
  2. The water droplets rise to colder altitudes, where they form large vapor clouds (thunderclouds) over the sea.
  3. The rapidly rising air creates a negative pressure on the sea surface, which draws in more humid air from the environment.
  4. The air masses are drawn upwards like in a chimney.
  5. The rising of these amounts of water releases energy.
  6. This energy causes the clouds to move and begin to rotate.
  7. Wind speeds of up to 350 kilometers per hour are generated.

Hurricane categories according to the Saffir-Simpson Hurricane Wind Scale (SSHS)

The Saffir-Simpson Hurricane Wind Scale divides hurricanes into different categories according to their wind speed and tidal height.

categories

wind speed

tidal waves

1 minimum

119 km/h to 153 km/h

1.5m to 1.8m

2 Moderate

154 km/h to 177 km/h

1.9m to 2.4m

3 Strong

178km/h to 209km/h

2.5m to 3.9m

4 Very strong

210km/h to 249km/h

4.0m to 5.5m

5 Disastrous

From 250 km/h

Higher than 5.5

consequences of hurricanes

The dangers and associated consequences of a hurricane are devastating. It is their wide diameter that makes the hurricanes so dangerous, since the extent of the damage can be several kilometers.

Heavy rainfall, high wind speeds and storm surges can cause catastrophic destruction through landslides and flooding. They destroy infrastructure, overhead lines, sanitary facilities and destroy sources of food and drinking water. Many people become homeless or pay with their lives as a result of a hurricane.

The probability of contracting diseases such as typhus, cholera or malaria also increases rapidly after a disaster caused by a hurricane, especially in tropical countries. This is dramatic when countries and population groups that are already poor are affected by the effects of the storms.

The deadliest hurricanes since 1900

The hurricanes that followed are remembered negatively for a particularly large amount of destruction.

  • 1900, Galveston Hurricane: Half of the Texan city of Galveston was destroyed, 6000 dead
  • 1928, Okeechobee hurricane: Numerous levees broke on the east coast of the USA, 2500 dead
  • 1969, Camille: In the states of Mississippi and Louisiana, nearly 300 people died and thousands were left homeless
  • 1974, Fifi: Honduras, Belize and Guatemala affected, 5000 people died in Honduras alone
  • 1979, David: 6000 homeless, 1000 dead
  • 1988, Gilbert: Raged for eight hours in Jamaica and the Greater Antilles, buildings and the airport were badly damaged
  • 1992, Andrew: 550 square kilometers in Florida devastated, damage of 25 billion dollars, 230 km/h fast, five meter high storm surge, 49 dead
  • 1998, Mitch: In Honduras he did terrible damage. He later migrated through Nicaragua, El Salvador and Guatemala, killing 12,000
  • 2004, Ivan: from Trinidad via Barbados, Grenada, Jamaica and Cuba to the southern United States, 124 dead
  • 2004, Jeanne: 3000 people died in Haiti alone before he moved to Florida via the Bahamas, 8 billion dollars in damage
  • 2005, Wilma: It also hit northwest Cuba badly, later the cyclone also reached Mexico and the USA. Flight of 600,000 residents and damage in the billions
  • 2007, Noel: Caribbean, 140 dead

hurricanes and climate change

Different climate models give reason to fear that there will not only be more hurricanes in the future, but also stronger ones. Many scientists believe that the man-made climate change is to blame.

According to some scientists, climate change is causing overall higher sea surface temperatures and thus even more favorable conditions for the formation of new hurricanes. The larger the sea areas with a temperature above 26 degrees, the larger the areas in which hurricanes can form.

However, this theory has not yet been scientifically confirmed. The researchers cannot distinguish whether natural fluctuations or the influence of greenhouse gases emitted by humans are responsible for the excessive warming in the regions concerned. Both are quite conceivable.

Early detection of hurricanes

A lot of time and money is invested in monitoring and early detection of hurricanes in order to provide early warning and protection to the population. Research is being conducted into how to prevent hurricanes from making landfall. There are several different methods for early detection and prevention.

A first approach is to use hoses to pump cold water from the depths to the sea surface to stop evaporation. But only with 10 million pumps working for 10 hours would the effect be large enough. However, since hurricanes often change direction, there is a high risk that the pumps will be in the wrong place.

Early detection therefore consists primarily of introducing a functioning warning management system. This begins with the first warning days before the storm hits, progresses to extensive and rapid evacuation efforts, and ends with rapid reconstruction and infrastructure restoration.

Hurricane – The Most Important

  • Hurricanes are a natural phenomenon that have catastrophic effects on people and their environment.
  • Hurricanes are tropical cyclones with wind speeds of up to 118 km/h.
  • They differ from the cyclone and typhoon in the place of origin.
  • Hurricanes are named by the WMO.
  • Hurricanes are cylindrical and their center is called the eye.
  • In the eye it is windless and cloudless.
  • Hurricanes occur from a water temperature of 26°C on large warmed-up ocean areas when there is a low-pressure area.
  • A hurricane is formed by the evaporation of water, which creates clouds. These begin to rotate due to released energy.
  • There are many theories about the link between climate change and hurricane frequency.
  • There is no solution for avoiding hurricanes, which is why the main focus is on warning systems for the population.