According to James Kossin, who works at the U.S. National Oceanic and Atmospheric Administration’s (NOAA) Center for Weather and Climate (University of Wisconsin–Madison), the speed at which hurricanes track along a paths is slower. This movement is called the translational speed and it is a factor to consider when assessing the potential damage and devastation that a hurricane may cause. Furthermore, the speed of this movement affects how much rain falls in an area.
Speaking with Laboratory Manager magazine, Kossin explains: “Just a 10 percent slowdown in hurricane translational speed can double the increase in rainfall totals caused by 1 degree Celsius of global warming.”
Kisson’s research examined 68 years (between 1949–2016) of worldwide hurricane track and intensity data (what is referred to as “best-track data”). These data were used NOAA to identify changes in translational speeds. The analysis discovered that, worldwide, hurricane translational speeds are averaging 10 percent lower across the time period.
The cause of this is attributed to climate change, or what Kossin and his colleagues refer to as “anthropogenic warming.” This creates some regional variations with the slowdown rates. With this, a warmer atmosphere can hold more water vapor, which potentially increases the amount of rain a hurricane can deliver to a given area.
As an example of the problem, the researchers discuss Hurricane Harvey, which stalled over eastern Texas in 2017, instead of dissipating over land as expected. The effect was to drench Houston and nearby areas with up to 50 inches of rain across several days, and causing considerable devastation.
More concerning, the problem is expected to get worse. Another study predicts that hurricanes will experience a 9 percent slowdown, higher wind speeds, and produce 24 percent more rainfall over the next few years.
The research has been published in the journal Nature. The research paper is “A global slowdown of tropical-cyclone translation speed.”
