"Hurricane Harvey past year was a great example of what a slow storm can do". "Not quite like a cork in a stream, but similar", he said.
Kossin told Nature that a 10% slow-down in storm speed corresponds to a 10% increase in rainfall when a hurricane makes landfall. But one scientist with the U.S. National Oceanic and Atmospheric Administration made a decision to look back in time, to see what happened in the past. It's 20 percent when storms reached land.
Therefore, it would make sense that if the flow around the hurricanes and typhoons is moving slowly, the storms will also be moving slower, which Kossin believes is what he is observing in the data.
Experts believe that continued global warming will increase the severity of tropical storms, but they also believe this anthropogenic warming will increase rainfall.
"The storms will stay in your neighbourhoods longer", he said.
Kossin would actually agree on that point. "At least not yet". Indeed, after around 1980, we could observe them by geostationary satellite - before that, storms in the open ocean might have been missed completely and gone unrecorded, at least if they never encountered any vessel. For instance, if exceptionally slow-moving storms have grown more likely in recent years, does that mean "stalled" storms like Harvey-which seemed to get stuck in place for days-are increasing, too?
But Kossin, in his paper, writes that he wouldn't expect big changes in his results due to different means of measurement, since "estimates of tropical-cyclone position should be comparatively insensitive to such changes".
While the new research suggests hurricanes and typhoons are slowing down over time, more work needs to be done to improve prediction models for how hurricanes may behave in the future. Follow him on Facebook, Twitter and Instagram.