We explain what tropical storms are, how they are classified and their formation. Also, what are its characteristics and consequences.
What are tropical storms?
Tropical storms are known as low pressure weather systems in which the winds rotate around a central axis in a closed circulation.
These storms are usually characterized by torrential rain and strong winds, the intensity and destructiveness of which vary mainly depending on the water temperature and air humidity of the place where the storms develop.
Depending on this intensity, tropical depressions (low intensity) are distinguished from tropical storms (medium intensity) and hurricanes or typhoons (high intensity). Some storms can be so large that they can be observed from the planet's outer atmosphere.
Cyclone or tropical storm? The terms cyclone and tropical storm are sometimes confused, but they do not mean the same thing. A cyclone is a weather system that has a low pressure center and winds that rotate in a circle. Cyclones can be small or very large, and can form in different parts of the world. A tropical storm is a specific type of tropical cyclone, with strong winds, more intense than those of a tropical depression but not as intense as those of a hurricane or typhoon.
Types of cyclones
There are several types of tropical cyclones that can be classified according to the intensity of their winds and their area of influence:
- tropical depression. It is the type of cyclone that presents lower intensity winds that do not exceed 65 kilometers per hour. Although they can generate heavy rain and moderate winds, they generally do not cause much property damage.
- Tropical storm. It is formed when the sustained winds of the tropical cyclone reach between 65 and 120 kilometers per hour. It is characterized by the presence of an “eye”, an area of relative atmospheric calm located in the center of the storm, surrounded by clouds and rain.
- Hurricane. It is a very intense tropical cyclone that forms when the winds exceed 120 square kilometers. Its extensive storm areas can exceed 1,000 kilometers in diameter and cause significant material damage and loss of human life. They are classified using the Saffir-Simpson scale into five categories, from 1 to 5, with number 5 being the most destructive.
- Typhoon. It has the same characteristics as a hurricane, but differs in the geographical location in which it forms. While hurricanes are tropical storms that form in the Atlantic Ocean, mainly in the Caribbean region, typhoons form in the Pacific Ocean, on the coasts of the Asian continent.
In addition to tropical ones, there are other types of cyclones, depending on the latitude at which they occur:
- Extratropical cyclones. They form in latitudes above 30°, outside of tropical areas.
- Subtropical cyclones. They form in subtropical areas and are usually less intense than extratropical cyclones.
- Polar cyclones. They arise in the polar regions and can generate snow storms.
How do tropical storms form?
Tropical storms form on the surface of the oceans from the combination of three elements:
- An area of low pressure and high temperature in the atmospherebecause tropical storms need warm air to form.
- High temperatures in ocean waters since tropical storms form over warm waters.
- High humidity in the atmospherenecessary for the formation of clouds and rain.
When these three factors combine, warm, moist air rises from the sea surface. As its height increases, it cools, condenses its water vapor particles and forms clouds. As storm formation progresses, the clouds become larger, more warm, moist air accumulates, and the tropical storm is created.
This circuit repeats as the storm gains energy and moves over the ocean, generating intense rain and storm fronts.
When the storm enters the continent, and no longer has the moisture of the ocean to feed on, it usually loses intensity and finally dissipates.
In tropical areas, high temperatures and humidity are two frequent climatic elements, especially in the spring and summer months when there is greater solar radiation and it is hotter. For this reason, tropical storms, although they can form at any time of the year, are more frequent in the warm months.
Consequences of tropical storms
Tropical storms can cause enormous damageeven when they do not become hurricanes.
The greatest damage is seen mainly in coastal areas, since upon entering the interior of the continents, these storms lose intensity and energy. In these areas near the sea, intense winds and rain can cause objects to fly, demolish homes, and cause flooding.
The arrival of these storms can have serious consequences for people and urban infrastructure. Recovery from areas affected by a tropical storm can take weeks, months or even years.
Rebuilding damaged infrastructure, clearing debris, and caring for affected people often require a large amount of resources and time to carry out.
In what season do tropical storms generate?
The highest incidence of tropical storms in the world occurs towards the end of summer, when the seas are warmer.
Although each region may have its own storm conditions and times, it has been observed that February is usually the least active month and September is the most active globally.
Typical tropical storm formation regions
The formation regions of tropical storms are found in the main oceans of the planet:
- North Atlantic. It includes the coast of North America, the Caribbean Sea and the Gulf of Mexico.
- North Pacific. It includes the Bering Sea, the Sea of Japan and the Yellow Sea.
- Southwest Pacific. It covers the coasts of Australia, Indonesia and the Philippines.
- North Indian. It covers the Bay of Bengal and the Arabian Sea.
- South Indian. It affects the coasts of Africa, western Australia and Antarctica. The occurrence of tropical storms in these regions is very rare.
How are tropical storms named?
Since 1950, tropical storms have been identified by people's names. At first they were called by women's names, and from 1970 men's names began to be used as well.
The names are chosen in alphabetical order. Thus, the name of the first storm will receive a name with A, the second with B and as the following storms occur, the initial of its name will change as the alphabet progresses.
This also serves to identify the number of storms that have occurred so far in a season. For example, if the storm is named “Iris,” this means it is the ninth tropical storm since counting began that year.
References
- National Geographic (2022). What is a hurricane? NationalGeographicLA
- World Meteorological Organization (WMO) (sf). Tropical cyclones. W.M.O.
- Pan American Health Organization (PAHO) (sf). Storms. PAHO
- Arriols, E. (2018). What is a typhoon and how is it formed? Green Ecology. EcologyGreen
