What makes a storm a hurricane? The dangers across 5 categories
Severe weather can affect any part of the world, but every year the Atlantic hurricane season brings heavy rain, strong winds, storm surge and sometimes catastrophic destruction in locations from the Caribbean islands and Central America to the United States and Canada.
Forecasters at the Miami-based National Hurricane Center monitor the storms from the time they develop until they dissipate. The 2024 season was supposed to take place this year extremely activeand it delivered the earliest Category 5 Atlantic hurricane registered.
But how do these hurricanes form and what do the categories mean? A look at the facts:
Hurricanes According to the National Oceanic and Atmospheric Administration, they often start as tropical waves that combine with warm ocean water. They can also be fanned by thunderstorms. The weather system is moving west as warm ocean air rises into it, creating an area of low pressure below it, NOAA said. Air rises and cools, forming clouds and thunderstorms.
Hurricanes have maximum sustained winds – the highest average one-minute wind speed at a given time – of 74 mph (120 km per hour) or higher. If a tropical cyclone has maximum sustained winds between 39 and 73 mph (63 km/h to 120 km/h), it is called a tropical storm. When maximum sustained winds are less than 60 km per hour, it is called a tropical depression.
Hurricanes typically occur during hurricane season, which occurs from June 1 to November 30 each year in the Atlantic Basin.
The Saffir-Simpson Hurricane Wind Scale rates hurricanes from one to five. Category 1 hurricanes range from 75 to 90 miles per hour and can bring very dangerous winds that can damage even sturdy homes. Category 1 is the weakest hurricane, and from there the storms strengthen the scale.
If a hurricane is Category 3 or higher, it is considered a major hurricane. Category 3 hurricanes begin with maximum sustained winds of 110 miles per hour.
Catastrophic. A Category 5 hurricane destroys homes, knocks out power in large areas and… isolates communities due to fallen trees and fallen electricity poles. It can also cause critical damage to infrastructure such as roads, bridges and dams. A Category 5 hurricane can make large areas uninhabitable for weeks or longer.
The toll of damage from a hurricane depends on its strength and where it makes landfall. Even a relatively weak hurricane can cause extensive damage and many deaths if it hits a vulnerable community or damages a key piece of infrastructure. A hurricane of medium strength such as Hurricane Jeanne in Florida in 2004 will cause devastating damage to homes, infrastructure and the electrical grid. Deaths are also common due to flooding, accidents, injuries and other disturbances caused by the storm.
The 1900 Galveston Hurricane in Texas is the deadliest natural disaster in U.S. history, according to NOAA and other authorities. The storm killed at least 8,000 people, destroyed thousands of buildings and left hundreds of millions of dollars in damage by today’s standards. There have also been other extremely deadly hurricanes in recent history Hurricane Mariawhich killed more than 3,000 people in 2017, and Hurricane Katrina, which killed more than 1,300 people in 2005.