Science

Hurricanes May Be Getting Slower, Making Them Even More Destructive

Hurricanes May Be Getting Slower, Making Them Even More Destructive

"Nothing good can come of a slower storm", Kossin told Mashable.

He said Hurricane Harvey in Texas a year ago was a dramatic example of the consequences of a slow-moving or "stalled" tropical cyclone.

The unusually slow-moving Hurricane Harvey was a recent example.

"Storms should be responding to changes in the whole global wind pattern, since they are mostly just carried along in the flow", Kossin said.

"If the atmosphere can hold more water vapor, then things are going to tend to rain more", Kossin said.

"What we're seeing nearly certainly reflects both natural and human-caused changes", Kossin said. The fact that their results show quite similar trends should be a wake-up call. "And that has effects on circulation - typically slows it down".

Although commending the study for its findings, she said it is not without its limitations.




This means the more time they spend above land, the more devastation they can wreak with rainfall and storm-induced damages. But when Atlantic storms hit land - like Harvey did in 2017 - the study said the slowdown is a significant 20%.

'This suggests that global warming can enhance rainfall'.

For instance, it is expected that hurricanes will rain about 7 to 10 percent more per degree Celsius (1.8 degrees Fahrenheit) of warming, as the atmosphere retains more water vapor, Kossin explained. Adding last year's storms would have made the slowdown a bit more prominent, he said.

A big storm that drops a lot of rain is more unsafe if it's going slow.

"Still, it's entirely plausible that local rainfall increases could actually be dominated by this slowdown rather than the expected rain-rate increases due to global warming".

"Long-duration or slower-moving storms, even when weaker, can have exacerbated impacts through prolonged wind exposure [in addition to] flooding", according to Colin Zarzycki, a project scientist with the National Center for Atmospheric Research who was not involved with the study. Instead, it means the tracks of the storms have slowed, allowing them to hover in one location for longer periods of time.