September, as well as the entire autumn, is the peak period for the formation of hurricanes. Hurricanes are also known as Tropical Cyclones – extensive low-pressure centers that form in the intertropical zone, generating continuous winds exceeding 115 km/h. They form at least 500 km north or south of the equator, in humid air, over warm ocean waters, the temperature of which exceeds 26.5 degrees Celsius.
A Monster in the Making: How Does a Hurricane Form?
The ocean heated by high temperatures in the summer months – begins to evaporate. Rising currents of warm air – cool at a certain height and condense – clouds are formed. The condensation process releases heat energy, strengthening the system of rising movements. During the rise of such air, the pressure in the center of the hurricane drops – a vast low center is formed over the ocean, with a characteristic, rotating ''eye of the cyclone'' with calm, cloudless weather.
It is the Coriolis Force, resulting from the Earth's rotation, that gives the hurricane its rotation, which allows it to organize and intensify. Outside the eye, completely different conditions prevail. The pressure can be higher by several dozen hPa, causing a huge pressure gradient, which is the cause of the destructive wind. It is accompanied by heavy rain with thunderstorms.
The movement of a cyclone near land sometimes leads to catastrophic property damage and is responsible for the deaths of thousands of people. In 1780, the Great Hurricane claimed the lives of over 22,000 people, and its wind gusts reached 325 km/h!
More than two centuries later, a scale of hurricane intensity was developed, which is defined on the 5-point Saffir-Simpson scale. The highest, 5, refers to winds above 250 km/h. In the 21st century, only a few such ''fives'' have formed. An example of such a natural disaster is Hurricane Irma.
Hurricane Irma. It hit Florida seven years ago
Irma formed on August 30, 2017, as a tropical storm near the Cape Verde Islands. Water temperatures in the western Atlantic Ocean ranged from 28 degrees Celsius to 30 degrees Celsius, which favored storm intensification.
After its birth over the ocean, Irma quickly became an extremely intense, top-category hurricane, striking the Caribbean Islands on September 5 and 6. It reached maximum sustained winds of 285 km/h, making it one of the strongest hurricanes on record in the Atlantic. It left significant damage in key areas such as Antigua and Barbuda, then Saint-Martin and Saint-Barthélemy, Anguilla, and the Virgin Islands.
On September 10, Irma reached Florida, reaching Category 4. Although the winds weakened slightly, it still had a huge force. The main impact occurred in the Florida Keys, where wind speeds reached 215 km/h. Then the hurricane moved towards the coast, near Marco Island and Fort Myers, then Tampa. However, Irma weakened with each passing hour. Despite this, the destruction was enormous. The element disappeared on September 12, 2017. After passing through Florida, the hurricane weakened and eventually turned into an atmospheric depression over the southeastern part of the United States, in the area of Alabama and Georgia
The tragic outcome of Hurricane Irma
The scale of the disaster following Irma's path was overwhelming. Many people lost their homes, and their additional services, such as stores, schools, and medical centers, were closed or destroyed. There was a shortage of medicine, food, and most importantly – loved ones who did not survive, or were separated and missing. Not only material aid was needed, but also psychological aid. Federal and state authorities declared Florida a natural disaster zone. Providing support for relief personnel and residents became a key task to restore residents, at least a minimal level of comfort.
In both the Caribbean and Florida, Irma killed at least 134 people, not just from wind. The event was accompanied by continuous, heavy rain. In some places, rainfall reached 300 mm, and water from rivers and seas exceeded natural barriers, causing floods.
The estimated damage was over 77 billion dollarsmaking Irma one of the costliest hurricanes on record. In Florida, about 6 million people were evacuated, one of the largest evacuations in U.S. history. In the Caribbean, recovery took years, and some islands needed international aid to return to their pre-hurricane condition. Hurricane Irma had the worst damage on the Caribbean island of Barbuda, where 95 percent of buildings were destroyed. On Saint Martin, the situation was equally dramatic.
Will the climate crisis fuel hurricanes?
Hurricane Irma is a reminder of the power of nature, and the potential impacts of the climate crisis. These events underscore the importance of emergency planning, and the importance of preparing for potential future threats. Learning from past experiences is key to minimizing the impacts of future disasters. Irma is a warning that natural disasters can affect people in ways that will never be forgotten.
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