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19 de out. de 2023 · Called hurricanes when they develop over the North Atlantic, central North Pacific, and eastern North Pacific, these rotating storms are known as cyclones when they form over the South Pacific and Indian Ocean, and typhoons when they develop in the Northwest Pacific.
- Overview
- How are hurricanes formed?
- Why hurricanes are dangerous
- How climate change affects hurricanes
Here’s how they form, why they can be so deadly, and how to best prepare for them.
Hurricanes combine unyielding winds and torrential rain to create some of Earth’s most powerful storms. When hurricanes near land, wind can cause devastating damage, even spawning tornadoes. But the bigger danger is rain, which can cause catastrophic, and often deadly, flooding.
These storms gain energy from warm water and its winds whirl in a characteristic circular motion. Tropical storms are named once winds pass 39 miles per hour, and are deemed hurricanes when winds pass 74 miles per hour. Hurricanes are rated by categories on the Saffir-Simpson scale.
The same type of storm has different names depending on the region of the world: “hurricanes” develop over the North Atlantic, central North Pacific, and eastern North Pacific, “cyclones” form over the South Pacific and Indian Ocean, and “typhoons“ develop in the Northwest Pacific.
Centuries ago European explorers learned the Indigenous Caribbean word hurakan, signifying evil spirits and weather gods, to describe the storms that battered their ships in the Caribbean.
The Atlantic Ocean’s hurricane season peaks from mid-August to late October and averages five to six hurricanes per year. While cyclones on the northern Indian Ocean typically form between April and December, with peak storm activity around May and November.
Hurricanes begin as tropical disturbances in warm ocean waters with surface temperatures of at least 80°F. Those low-pressure systems are fed by energy from warm seas.
A storm with wind speeds of 38 miles an hour or less is classified as a tropical depression. It becomes a tropical storm—and is given a name, according to conventions determined by the World Meteorological Organization—when its sustained wind speeds top 39 miles an hour.
(National Geographic's role in the history of storm mapping.)
Hurricanes are enormous heat engines that deliver energy on a staggering scale. They draw heat from warm, moist ocean air and release it through condensation of water vapor in thunderstorms.
Hurricanes bring destruction ashore in many different ways. When a hurricane makes landfall, it often produces a devastating storm surge—ocean water pushed ashore by wind—that can reach 20 feet (6 meters) high and move several miles inland.
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Hurricanes 101
Hurricanes are massive storms with deadly force. Find out how they form, and what's being done to better predict their impact.
Storm surges and flooding are the two most dangerous aspects of hurricanes, accounting for three-quarters of deaths from Atlantic tropical cyclones, according to a 2014 study. A third of the 1,200 deaths from Hurricane Katrina, which made landfall off the coast of Louisiana in 2005, were caused by drowning. Katrina is also the costliest hurricane on record, with damage totaling $125 billion.
(How to prepare and keep safe in a hurricane.)
Climate change may be driving more frequent, more intense extreme weather, and that includes hurricanes. The 2018 hurricane season was one of the most active on record, with 22 major hurricanes in the Northern Hemisphere in under three months, and 2017 also saw seriously devastating Atlantic storms. While a number of factors determine a hurricane's strength and impact, warmer temperatures in certain locations play an important role. In the Atlantic, warming in the Arctic could drive future hurricane tracks farther west, making a U.S. landfall more likely.
(Are there solutions to climate change?)
Hurricane Harvey, which dropped a record-breaking 51.8 inches of rain on southeastern Texas in 2017, was fueled by surface waters in the Gulf of Mexico that were 2°F warmer than three decades before. A warmer atmosphere can also furnish more water vapor for making rain, as evaporation increases and warm air holds more vapor than cold.
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Rare Footage of Some of the World's Worst Natural Disasters
Warming temperatures can also slow tropical cyclones, which can be a problem if their progression over land is extended, potentially increasing storm surges, rainfall, and exposure to high winds.
1 de mai. de 2020 · weather. hurricanes. education. Share: Hurricanes are one of nature’s most powerful storms. They produce strong winds, storm surge flooding, and heavy rainfall that can lead to inland flooding, tornadoes, and rip currents. Hurricane Humberto, as captured by a NOAA satellite September 15, 2019. (Image credit: NOAA Satellites) Download Image.
The short answer is that there is none. They are all organized storm systems that form over warm ocean waters, rotate around areas of low pressure, and have wind speeds of at least 74 mph (119 km per hour). The reason for the three names is that these storms are called different things in different places.
14 de set. de 2018 · In the North Atlantic Ocean and Northeast Pacific, they are called hurricanes. But if the same type of disturbance takes place in the Northwest Pacific Ocean, it is known as a typhoon. And in the...
7 de mai. de 2024 · Tropical cyclone, an intense circular storm that originates over warm tropical oceans and is characterized by low atmospheric pressure, high winds, and heavy rain. Also called typhoons and hurricanes, cyclones strike regions as far apart as the Gulf Coast of North America, northwestern Australia, and eastern India.
16 de set. de 2020 · As we enter hurricane season, when there is a greater chance of more powerful storms developing in the Atlantic, here is a guide to how deadly storms form, how they are measured and why they...
