The Atlantic Hurricane Nana has recently made headlines as it pounded on the coast of Belize. This event comes shortly after Hurricane Laura hit southwestern Louisiana (South Central United States). Belize, where Nana made its landfall, is situated on the northeast coastal region of Central America.
Understanding Tropical Cyclones
A hurricane, like Nana and Laura, is a type of tropical cyclone. These are low-pressure weather systems that form over tropical or subtropical waters. What differentiates them from other weather systems is their lack of fronts, which are boundaries separating air masses of different densities. Instead, tropical cyclones boast organized thunderstorms.
Speed of Winds: Identifying Depressions, Storms, and Hurricanes
A determining factor of whether a tropical cyclone is a depression, storm, or hurricane is its maximum sustained surface winds. Systems with speeds less than 39 miles per hour (mph) earn the label of tropical depressions. To be classified as a tropical storm, winds must reach a minimum of 39 mph. Finally, when the storm’s maximum sustained winds attain a speed of 74 mph, it is officially designated as a hurricane.
Saffir-Simpson Hurricane Wind Scale: Measuring Wind Speed
The strength of a hurricane is measured using the Saffir-Simpson Hurricane Wind Scale. This categorizes hurricanes on a rating from 1 to 5, taking into account the hurricane’s maximum sustained winds. The higher the category, the more potential for property damage.
Conditions for Formation
To form a hurricane, certain environmental conditions need to be present. Primarily, there should be warm ocean water and a humid atmospheric condition present in the region. When moist air rises in a low-pressure zone above warm ocean water, the water vapor is released from the air, forming clouds that constitute the storm.
Characteristics of a Tropical Cyclone
A tropical cyclone features a low-pressure center and spiraling clouds that move towards the eyewall surrounding the “eye”. This central part of the system is typically free of clouds and calm. The diameter of these storms generally ranges from 200 to 500 km, but it can reach up to 1000 km.
In the Northern Hemisphere, the winds blow counterclockwise, whereas in the Southern Hemisphere, they travel clockwise. Along with violent winds, tropical cyclones bring torrential rain, high waves, and occasionally, highly destructive storm surges and coastal flooding.
Different Names Based on Locations
The name given to a tropical cyclone varies depending on its location. In the Caribbean Sea, Gulf of Mexico, North Atlantic Ocean, and the eastern and central North Pacific Ocean, they are referred to as hurricanes. They are called typhoons in the Western North Pacific. In contrast, the term cyclone is used in the Bay of Bengal and Arabian Sea. Australia refers to them as willy-willies.
Last Modified: February 9, 2024