Hurricane Speed
What is the maximum speed that a hurricane reaches?
Hurricane Milton, which is expected to hit the Florida coast soon, seemed to come out of nowhere: it was just a tropical storm, but it advanced to Category 5, with winds of 180 mph. But how close is Milton to the maximum speed a hurricane can reach? Is there a limit? There is a "speed limit" to the intensity of sustained winds, called maximum potential intensity, but it is not absolute: it is dictated by several factors, including the heat present in the oceans. Currently, calculations of the maximum potential intensity for storms generally peak at around 200 mph.
However, this could change in the coming decades as the oceans warm and the climate changes. The potential for severe storms has already been increasing over the past 30 years, according to Kerry Emanuel, professor emeritus of atmospheric sciences at MIT, who developed the model. Truly monstrous storms are also more frequent: five recorded storms had winds exceeding 200 mph, all occurring since 2013. "I believe that, by the end of the century, if we don't do much to contain emissions, this number could approach 220 mph," Emanuel said.
What fuels a storm
A hurricane's wind speed threshold is relatively easy to calculate, says James Kossin, a retired climate scientist who now serves as a consultant for the climate risk modeling agency. "The fuel for hurricanes is the heat they absorb from the oceans," Kossin explained. "The hotter the water, the more fuel is available." Other factors also determine maximum potential intensity, such as heat in the atmosphere and cloud top temperature, which defines how quickly heat moves from the sea surface to the top of the storm, as well as wind shear, which is the difference in wind speed and direction at different heights in the atmosphere.
Too much shear can tear a storm apart, weakening it and preventing it from reaching its full potential. A study of storms between 1962 and 1992 showed that only 20% of Atlantic cyclones reach 80% or more of their maximum potential intensity, although there is evidence that a greater proportion of storms are coming closer to that theoretical limit, according to Emanuel.
As the oceans and atmosphere warm, storms are getting stronger. In 2020, Kossin and his colleagues reported that the proportion of major hurricanes increased by 8% per decade between 1979 and 2017. This means that as the climate warms, intense, rapidly intensifying storms like Milton could become alarmingly common.
New hurricane categories?
Hurricanes are classified on the Saffir-Simpson scale, which ranges from category 1 (sustained winds from 119 km/h) to category 5 (sustained winds from 252 km/h). However, this scale is incomplete as it is based solely on wind speed without considering damage caused by storm surges or flooding, which are more deadly than winds, Emanuel said.
The increasing likelihood of severe storms prompted Kossin and his colleague Michael Wehner of Lawrence Berkeley National Laboratory to suggest in February the creation of a "Category 6" for the Saffir-Simpson scale, which would include storms with winds above 198 mph h. The researchers identified five storms that would already qualify for this category: Typhoon Haiyan (2013), Hurricane Patricia (2015), Typhoon Meranti (2016), Typhoon Goni (2020) and Typhoon Surigae (2021). Patricia was the most intense on record, with winds of 345 km/h, although it weakened to 241 km/h before making landfall.
Wehner and Kossin considered a possible "Category 7" for hurricanes with winds above 220 mph (368 km/h). However, their calculations showed that there is currently a negligible risk of such strong storms, Wehner told Jornal Paraná, so they did not include this possibility in the study. No one knows for sure how fast a hurricane's winds could reach if ocean temperatures continue to rise, Wehner said. "In really intense eyewalls, where the winds are at full tilt, these flows are very unstable," he said.
The exact dynamics of the eyewall are not yet fully understood. Milton's weakening occurred following eyewall replacement, which happens when a new band of thunderstorms forms around the eye of the storm, cutting off moisture from the original eyewall. This change redistributed Milton's energy, increasing the storm's overall size but decreasing the intensity of its winds. It may be that at extreme wind speeds these storm weakening phenomena become unavoidable, but this is not yet well understood, Wehner concluded.
Interested in upgrading to Low E impact glass windows for your home? Contact us today for a free consultation and discover how this cutting edge technology can save you money, improve your home's security, and provide long lasting protection.
Understanding hurricane speeds and their potential impact on your property is crucial for staying safe. Don't leave your home vulnerable when the next storm hits! Upgrade your windows with impact resistant glass and enhance your home's hurricane protection today. With expert installation of stormproof windows and doors, you can ensure your property is safe from high winds and flying debris. Contact us now for a free consultation on the best hurricane proof solutions for your home and start preparing for the next hurricane season.