Both tornadoes and hurricanes are characterized by extremely strong horizontal winds that swirl around their center and by a ring of strong upward motion surrounding downward motion in their center. In both tornadoes and hurricanes, the tangential wind speed far exceeds the speed of radial inflow or of vertical motion.
Hurricane Ian made landfall in Florida as a category 4 storm with 150 mph winds, making it one of the strongest storms ever to hit the U.S. mainland. That ties for fifth-strongest at landfall, based on maximum sustained wind speeds.
Ian almost hit as a category 5 storm, the wind speed threshold for that is 157 mph or higher (learn more about hurricane categories here). Only four hurricanes of that caliber have held that strength as they made landfall on the U.S. mainland.
Hurricane Katrina, for example, was far more devastating in terms of loss of life and infrastructure when it made landfall near New Orleans in 2005, but it was a category 3 when it did. So where does Ian rank all time? Here’s what NOAA says.
Hurricanes always and tornadoes usually rotate counterclockwise in the northern hemisphere and clockwise in the southern hemisphere. The Earth’s rotation determines this direction for the storms’ rotation in each hemisphere. Local winds are sometimes able to cause a tornado to form that spins in the opposite direction from the typical direction for that hemisphere.
The most obvious difference between a tornadoe and hurricane is that a hurricane’s horizontal scale is about a thousand times larger than a tornado. In addition, hurricanes and tornadoes form under different circumstances and have different impacts on the atmosphere.
Tornadoes are small-scale circulations, that are rarely more than a few hundred feet across when they touch the ground. Most tornadoes grow out of severe thunderstorms that develop in the high wind-shear environment of the United States Central Plains during spring and early summer. Many tornadoes form when the large-scale wind flow leads to a violent clash between moist, warm air traveling north from the Gulf of Mexico and cold, dry, continental air coming from the United States Northwest. Tornadoes can also form in many other locations and from other forcing factors. For example, a hurricane making landfall may trigger many tornadoes to form.
Tornado wind speeds may reach 100 to 300 mph and cause havoc on the ground, but tornadoes typically last only a few minutes and rarely travel more than 10 or 20 miles along the ground. Tornadoes have little impact on storms that spawn them or collectively on the global circulation of the atmosphere.
Hurricanes, on the other hand, are large-scale circulations that are 60 to over 1,000 miles across. Hurricanes form near the Equator, generally between 5 and 20 degrees latitude, but never right on the Equator. Hurricanes always form over the warm waters of the tropical oceans and generally where the sea-surface temperature exceeds 26.5°C (76°F).
A hurricane may travel thousands of miles and persist over several days or weeks. During its lifetime, a hurricane will transport a significant amount of heat up from the ocean surface and into the upper troposphere or even lower stratosphere. Even though hurricanes form only sporadically, they do affect the global atmosphere’s circulation in measurable ways, although this is still an active area of research.
Hurricane Ian Forms South of Cuba
GPM overpass of Hurricane Ian on Sept. 26, 2022
Thursday, September 29, 2022
Hurricane Ian became one of the strongest hurricanes on record to strike Florida when it made landfall Wednesday, Sept. 28th, 2022, around 3:10 pm (EDT) as a Category 4 storm near Cayo Costa, FL, about 20 miles west-southwest of Punta Gorda on Florida’s southwest coast. This same area was hit hard by Hurricane Charley in 2004, which also made landfall as a strong Category 4 storm. Both storms passed over and were intensified by the deep, warm waters of the southeastern Gulf of Mexico. Ian originated from a tropical easterly wave that propagated westward off the coast of Africa across the
…
Hurricane Ian Reintensifies en Route to Florida
IMERG analysis of Hurricane Ian
Wednesday, September 28, 2022
Passing over western Cuba on Sept. 27, 2022, Hurricane Ian weakened somewhat. Subsequently, Ian re-intensified on its way to an expected landfall on Florida’s west coast on Sept. 28. NASA and other organizations collected observations of Hurricane Ian while it was in the Gulf of Mexico on Sept. 27 and 28. In the Gulf of Mexico, Ian’s eyewall was seen to contain particularly vigorous storm cells. Lightning was observed in Ian’s eyewall, whereas lightning had been near absent from Ian’s eyewall prior Ian passing over Cuba. Lightning flashes from the World Wide Lightning Location Network (WWLLN)
…
Hurricane Ian Makes Landfall in Cuba on Route to the U.S. Gulf Coast
… Hurricane Ian
Tuesday, September 27, 2022
Hurricane Ian formed in the Caribbean Sea on Sept. 26, 2022. Ian intensified to Category 3 hurricane on the Saffir-Simpson scale by the time it made landfall in western Cuba early the next day. NASA’s near real-time IMERG algorithm was used to estimate the precipitation from Ian during its formation and intensification. IMERG shows that Ian’s largest rainfall accumulation so far, over 12 inches, occurred while it was only a tropical storm and not yet a hurricane. The National Hurricane Center provided an estimate of the distance that tropical storm-force winds extended from Ian’s low-pressure
…
Fiona Becomes a Major Hurricane in the Atlantic
GPM overpass of Hurricane Fiona on Sept. 23, 2022.
Tuesday, September 27, 2022
After leaving the Caribbean, Hurricane Fiona became both the strongest and the first major hurricane of the 2022 Atlantic hurricane season as it made its way northward through the western Atlantic. Fiona began as an African easterly wave that moved across the tropical Atlantic in the direction of the Caribbean. While still about 800 miles east of the Leeward Isles, this wave organized into a tropical depression on Sept.14th. Later that same day, the depression strengthened and became Tropical Storm Fiona. Fiona remained a moderate tropical storm as it passed through the Leeward Isles on the
…
Hurricane Fiona’s Caribbean and Canadian Landfalls
…estimates from Hurricane Fiona
Monday, September 26, 2022
In September 2022, Hurricane Fiona had impacts in the Caribbean, on Bermuda, and in Canada. NASA’s satellites and science algorithms helped to monitor this hurricane in near real time.
…