Research indicates that the speed of hurricanes worldwide has significantly slowed down, yet their intensity and potential for destruction have increased.
Hurricanes are often described as “sweeping through” a specific area. However, in recent years, unusual paths have emerged, with storms meandering and lingering for days on end. This phenomenon is termed “stationary storms.”
Hurricane Harvey, moving slowly in Texas, USA, causing significant damage. (Photo: NASA).
A study published in the journal Nature reveals that hurricanes globally have moved at a significantly slower pace over the past 65 years. This trend is accompanied by heavy rainfall and rising sea levels.
Specifically, hurricanes have slowed down by an average of 10% from 1949 to 2016. The study directly cites Hurricane Harvey, which caused devastating rainfall in Houston, USA, as it “lingered” in the area for an extended period.
Jim Kossin, a scientist at the National Oceanic and Atmospheric Administration (NOAA) and a co-author of the study, states that slower-moving hurricanes will lead to more rainfall in a specific area. They also continuously wreak havoc with their powerful winds.
On the other hand, the slower a hurricane moves over the ocean, the greater its wind speed, water volume, and internal energy accumulation will be, thereby increasing its potential for damage. “Every hazard that a tropical storm possesses will have a longer impact. That is never a good thing,” Kossin remarked.
One of the factors affecting the speed of hurricanes is global warming. Climate change influences the overall circulation patterns on a global scale, where hurricanes take refuge and develop. Notably, the slowdown in air circulation, due to polar regions warming compared to the equator, also contributes to the deceleration of hurricanes.
Moreover, slow-moving hurricanes can cause prolonged damage over vast areas of land. Kossin’s report indicates that hurricanes originating from the Atlantic have moved 20% slower when making landfall over the past 70 years.
Rising temperatures also correlate with increased rainfall. The report estimates an increase of 7-10% in rainfall for every degree Celsius increase. The reason is that higher temperatures allow the atmosphere to retain more moisture. Meanwhile, the speed of hurricanes has decreased by about 10% with just a half-degree Celsius rise in global temperatures. These two combined trends are making hurricanes increasingly terrifying, with the slowdown being a more severe factor that enhances their strength.
