Claim: Hurricanes are slowing down, and that’s bad news

From the UNIVERSITY OF WISCONSIN-MADISON and the “yes but we need Category 6 now due to violently increased wind speeds” department comes this gloom and doom study.

MADISON, Wis. — Some hurricanes are moving more slowly, spending increased time over land and leading to catastrophic local rainfall and flooding, according to a new study published Wednesday (June 6) in the journal Nature.

While hurricanes batter coastal regions with destructive wind speeds, study author James Kossin says the speed at which hurricanes track along their paths — their translational speed — can also play a role in the damage and devastation they cause. Their movement influences how much rain falls in a given area.

This is especially true as global temperatures increase.

“Just a 10 percent slowdown in hurricane translational speed can double the increase in rainfall totals caused by 1 degree Celsius of global warming,” says Kossin, a researcher at the National Oceanic and Atmospheric Administration’s (NOAA) Center for Weather and Climate. He is based at the University of Wisconsin-Madison.

The study compared 68 years (1949-2016) of worldwide hurricane track and intensity data, known as best-track data, from NOAA to identify changes in translational speeds. It found that, worldwide, hurricane translational speeds have averaged a 10 percent slowdown in that time.

One recent storm highlights the potential consequences of this slowing trend. In 2017, Hurricane Harvey stalled over eastern Texas rather than dissipating over land, as hurricanes tend to do. It drenched Houston and nearby areas with as much as 50 inches of rain over several days, shattering historic records and leaving some areas under several feet of water.

How much hurricanes have slowed depends on where they occur, Kossin found. “There is regional variation in the slowdown rates when looking at the 10 percent global average across the same time frame,” he says.

The most significant slowdown, 20 percent, occurred in the Western North Pacific Region, an area that includes Southeast Asia. Nearby, in the Australian Region, Kossin identified a reduction of 15 percent. In the North Atlantic Region, which includes the U.S., Kossin found a 6 percent slowdown in the speeds at which hurricanes move.

When further isolating the analysis to hurricane speeds over land, where their impact is greatest, Kossin found that slowdown rates can be even greater. Hurricanes over land in the North Atlantic have slowed by as much as 20 percent, and those in the Western North Pacific as much as 30 percent.

Kossin attributes this, in part, to the effects of climate change, amplified by human activity. Hurricanes move from place to place based on the strength of environmental steering winds that push them along. But as the Earth’s atmosphere warms, these winds may weaken, particularly in places like the tropics, where hurricanes frequently occur, leading to slower-moving storms.

Additionally, a warmer atmosphere can hold more water vapor, potentially increasing the amount of rain a hurricane can deliver to an area.

The study complements others that demonstrate climate change is affecting hurricane behavior.

For instance, in 2014, Kossin showed that hurricanes are reaching their maximum intensities further from the tropics, shifting toward the poles in both the Northern and Southern Hemispheres. These shifts can deliver hurricanes to areas — including some heavily populated coastal regions — that have not historically dealt with direct hits from storms and the devastating losses of life and property that can result.

Another study, published in April by researchers at the National Center for Atmospheric Research, used a modeling approach to look at what would happen to hurricanes under future climate projections. Using real hurricane data from 2000-2013, the researchers found future hurricanes will experience a 9 percent slowdown, higher wind speeds, and produce 24 percent more rainfall.

“The rainfalls associated with the ‘stall’ of 2017’s Hurricane Harvey in the Houston, Texas, area provided a dramatic example of the relationship between regional rainfall amounts and hurricane translation speeds,” says Kossin. “In addition to other factors affecting hurricanes, like intensification and poleward migration, these slowdowns are likely to make future storms more dangerous and costly.”


The study was supported by NOAA’s National Centers for Environmental Information.


Leave a Reply

26 Comment threads
20 Thread replies
Most reacted comment
Hottest comment thread
35 Comment authors

newest oldest most voted
Notify of
Joel Snider

It’s pretty much always bad, isn’t it?
I wonder if there is, in warmist philosophy, a positive weather development.
Warmer, colder, stasis, more hurricanes, less hurricanes, more snow, less snow – all of it – just bad, bad, bad.
It’s kind of a weird hybrid of pessimism and mud-slinging.
Oh, well, I guess they go with their strengths.

Tom Halla

The parallel to “if it bleeds, it leads” in the news business?


No, it’s really good for sailors/shipping. The slower the storm, the easier they are to avoid (presuming you’re in open ocean, if you have to anchor, it’s bad for timetables.)


I don’t buy the statistical analysis of the speed of the storms over past decades or the suggestion that the cause is due to global warming “amplified by human warming.” Other than that it looks like a dandy study. I’m sure it contains all the necessary alarmist buzzwords so future grant requests will be fully funded.

Yes, my understanding is that Houston is known as an area where storms slow down. So, if a storm hits Houston, then the trend is for storms slowing down, but if storms stay away from the Houston region, then the translational trend will be lengthened.

I expect that they should have identified cities that have had multiple hurricane hits over that time period and compared the storm movements.

BTW, any idea why they chose that start year?

Patrick J Wood

More fake news. Harvey stalled because of a high pressure area sitting over West Texas.


Hold the bus!

“Kossin attributes this, in part, to the effects of climate change, amplified by human activity.”

Forgive me if I’m presenting myself as even more dense than usual, but this would be the 2 ppm CO2 man allegedly adds to the atmosphere, that has nowhere, other than in computer models and green imagination, ever been empirically demonstrated to cause warming?

And with the greatest of respect to Kossin, an eminent scientist I’m sure, whilst I don’t have a qualification to my name, I have the ability to ask for conclusive (even convincing) empirical evidence that CO2, never mind man made CO2, is the root cause of climate change, but he doesn’t seem to need that reassurance. And that’s not evidence that comes out a test tube, in laboratories, then extrapolated out, ignoring all the other influencing factors.

Is it me that’s wrong here?

I think the human contribution to CO2 is closer to 140 ppm.


Yeah. On the other hand, what causes warming is not 140 ppm, but only part of it, since much of the warming has already happened. Or so they say.

Well, according to some, the pipeline is long. We’ll see, unless we die and the pipeline is very long, right?

I refuse to panic. I see beneficial fuels, beneficial warming, and lots of opportunies for humans to develop new sources of energy, and even fixing climate that has become too warm too quickly.



“I refuse to panic.”

Mate, I see nothing but opportunity with a warming world.

Perhaps I’m just a blind optimist, but with NASA telling us the planet has greened as a matter of empirical fact, and no other observable downside to increased atmospheric CO2, I don’t think it’s an unreasonable position.

If we get warming, apparently it’s in the northern and southern latitudes, in winter, and at night.

That might mean the vast areas of Russia and Canada currently suffering perma frost are released to agriculture. What can possibly be negative about that?

It might mean equatorial regions get more rain, both the rainforests and deserts benefit. What can possibly be wrong with that?

So sea levels rise and all the beach-side condo’s are wiped out. Big effing deal. There will be a new beach somewhere to build a condo on.

For a race that evolved as a nomadic entity, we sure place a lot of emphasis on not moving these days.



I should have qualified that by saying 2 ppm per year.

There is also the life (or half life?) of CO2 to be considered in that estimate. 5 – 10 years as I understand it, so what humankind produced 10 years ago, aint there now, is it?

And as every human breathes out 40,000 ppm with every puff, is that allowed for in the estimates of human CO2 emissions, or is it only burning stuff that’s counted? There are an awful lot of us after all.


Jeff in Calgary:

A) A gross assumption that the entire increase in CO₂ occurring during over a century, is all caused by man; ignoring the fact that mankind is a minor CO₂ source.

B) 140 ppm is still 140 parts per million, an irrational thought to many people as they are unable to understand what 140 molecules in 1,000,000 molecules actually means.

Breaking that down to numbers people can absorb, frames that 140 ppm as 1.4 pptt (parts per ten thousand). Which factually means a 1.4 CO₂ molecule increase per 10,000 atmospheric molecules, during that greater than hundred year span.

According to alarmists, that magic mystical CO₂ molecule somehow drastically heat up 9,998.6 atmospheric molecules, along with all molecules on Earth’s surface while driving warmth deep into the oceans without a defined process mechanism, etc.

At no point do alarmists consider millions of years of natural CO₂ fluctuations, nor do they consider that 280 ppm is a CO₂ starvation range for most plants.


A jet stream from the northwest will block two tropical storms in the Eastern Pacific.
comment image


It’s 1/2 a friggin degree……….adjusted


Yeah, that’s the funny part. After some very very long pondering, adjustments have revealed the true extent of warming. We didn’t immediately notice it outside the congress hearing, but after a statistical massaging we can see the evidence everywhere: sea level in Stockholm, drought in Sahel and Texas, eternal drought in California and Oz, wars in Middle East, Carteret becoming inhabitable, Greenland collapsing and giving space to agriculture, Antarctic sea ice extent pointing down so that it will be the last habitable continent, and polar bears facing extinction when the north pole melted.

We’re so lucky we have good statisticians to show how the world is collapsing. I will remember to switch off the toilet lamp tonight.



please don’t switch off the toilet lamp tonight, it contributes to increased atmospheric CO2, which is really, really good stuff.


And in almost the same breath, as this study arrived in my inbox, another, almost entirely contradictory one from Paul Homewood at notalotofpeopleknowthat arrived.


1)Is there evidence that hurricanes are slowing down?
2) If so, can anyone provide proof that CO2 is behind it? Or are we just supposed to assume that correlation is causation?

Bob Turner


With this statement as one of the first.

“These changes vary by region and time of year, but there is evidence that anthropogenic warming causes a general weakening of summertime tropical circulation.”

Followed by 8 papers supporting it. The first, it seems, by Michael Mann.

Fine, I can’t read these papers because I’m not educated enough to understand them.

However, what I do understand is that there is no empirical evidence of CO2 affecting the climate.

So how is it possible that a scientific paper leads it findings by assuming that something that has never been observed in the real world is unquestionable?

It truly upsets me that the people I invest my faith in, represent me so badly.


They want you to pay to read the paper, which I will not do. However, in the synopsis I read of it, the article stated also they did not come to any conclusions on what was slowing down the hurricanes at all. So is it warming or something else?


Poppycock. “Research, used a modeling approach to look at what would happen to hurricanes under future climate projections. Using real hurricane data from 2000-2013…” So more models based on failed models using a period of data that had reduced hurricanes making landfall.

Paul Sarmiento

No, they used real data to form the models. Unfortunately, 2000-2013 data is nearly not long enough as hurricane season goes. Why did they limit it to such a short period when they could analyze data from 1900 onward.


They had a 50-50 chance that “speed” would be slower in more “recent” years, and a 50-50 chance that the slow-down would have been greater on land versus over water. This one-in-four chance far exceeds “p = point oh five.”

I cannot wait to get these data and enter them into the stats data set I have, which includes, from this zero-year of 1950, ACE, named tropical storms, hurricanes, and “major” hurricanes – which when analyzed any of several possible ways (simple correlation between year and any of these, chi-squared for first 20 years in data set versus most recent 20 years, etc.) shows NO increase in any of these measures of hurricane frequency or severity.

I hope the data are readily available, as these other metrics are – at Wikipedia under “accumulated cyclonic energy.”


You guys should pull up this article. It looks like from 1950 to 2016, hurricanes, overall, have been traveling 1.5 km/hour slower.

Is this within the range of normal variation? Or not? If we had 10 such periods going back in time, would we find 6-year slow-downs and speed-ups of this magnitude? Or greater?

We have no baseline against which to gauge this trend.

We could parse the entire data span into decades, or a couple 30-year spans, but the slow-down would disappear. For Southern Hemisphere, we would see two notable rises, with a step-down in between the two . Does climate behave in a linear way, or a quantum way? Or both?

Louis Hunt

How accurately could they measure the speed of hurricanes in the 50’s? Is 1.5 km/hour within the margin of error? And how many adjustments have been applied to the data over the intervening years? There seem to be too many questionable factors to say whether such small trends in the data are even significant, let alone claim the cause to be global warming.

I would like to know, if you removed Harvey from the data, would that result in no trend, or even a trend of speeding up? Harvey being right near the end of the data series makes any speed changes look larger than the true value.

J Mac

Hurricanes and typhoons have been operative for thousands of years. The UW-Madison study examined data from 1949-2016, just 68 years. It is not at all surprising that hurricane translational speeds show variability and some pseudo-trends for this ‘snapshot’ in time. Same goes for associated rainfall trends, over land or sea. Are the trends truly significant, given the limitations of our data and knowledge? Who knows?! The baseline period is too short and the data inadequate, as it does not incorporate enough natural climate cycles and natural cyclic variability to provide baseline perspective.

Yet another study that should start with the preface “Given our current lack of sufficient baseline data, knowledge, and understanding, we attempted to analyze….”

Robert W Turner

They used the “best-track” database put together by NOAA. I assume this “data” has had NOAA’s special touch added and is now better than raw data, how could it not be, it’s in the name after all.

So it seems they are now accepting that a warming planet will result in a smaller temperature difference between the tropics and poles, it’s how they tie global warming to slower translational speeds. But they still model storms becoming stronger despite a scenario that decreases vertical instability?

Let’s assume there has been a 10% slowdown (~2km/hr) slowdown in cyclone speeds, could there be another reason besides sampling or the evil CO2 molecule? Yeah, I’ll just leave these here:
comment image

Oh gee, hurricane landfalls are down in the same period included in their study. Even most laymen know that hurricanes typically accelerate quickly once the eye is over land. I wonder what it feels like having your research basically torn to shreds after a 5 minute internet search.

Robert W Turner

The Pielke graph is supposed to be addressed to a graph showing global landfalls, but you get the picture. It basically shows the same trend.


I can’t see anything coming out of the the University of Wisconsin-Madison without thinking that it is always among the top ten of party schools.


Ah, UW-Madison… the Berkeley of the Midwest….

michael hart

“Some hurricanes are moving more slowly…”

Yes, indeed. Look closely and you’ll also find that some hurricanes always did move more slowly (just like the buffalo, or herds of cats on a hot tin roof). And some moved more quickly.

Where do we get these people?

Stephen Singer

The Houston hurricane is an outlier in this story. The issue with it was it was blocked from moving on by a stalled High Pressure North of it. So, the Houston area got several times the water dumped on it that normally would have happened. The winds were not particularly high they just lasted extra long.


Dr. Maue reviewed a bit of older hurricane information over the last couple days. Quite interesting stuff in little chunks.

Robert of Texas

I wonder if one throws out all hurricanes that do not make landfall (we couldn’t see them using satellites in 1940) then I wonder if the discrepancy fades away? (can’t get to the paper, its behind a paywall).

Surely a “trend” using data from 2000 to 2013 is too small a sample to draw ANY conclusions. There could be all sorts of missed cycles or just random noise from such a small sample.

Why not just go look at rainfall records of hurricanes and see if there is a trend? Those go back over a hundred years. Oh, wait…they used a model in place of real data, so that’s better – easier to get the answers they want. LOL

John in Redding

I would be very skeptical of data showing a trend that hurricanes travel is slowing down. Each storm is so different such that it is hard to say there has been a 10% reduction. Storms speed up or slow down throughout the course of the storm. How do you realisticly evaluate that variable? That 10% is such a small number itself as to be meaningless.


“Hurricanes move from place to place based on the strength of environmental steering winds that push them along. But as the Earth’s atmosphere warms, these winds may weaken…”

No, the winds are weakening because all the wind turbines are sucking the energy out of them. It is the push for renewables and not climate change that is causing the slower hurricanes. And there is as much science behind my claim as behind the claim of the study’s author.


O.T. but…interesting
“Why climate change has run its course

Robert B

I saw it coming after I read this

The proximate cause of the disaster is clear: the extreme rainfall was the result of a hurricane/tropical storm that pulled in huge amounts of water vapor off the Gulf of Mexico (and beyond), and which came into the Texas coast and then stalled for days. All tropical storms/hurricanes bring large amounts of rain during landfall. What was different here was the stalling and sitting over the same region for days.

So if you want to explain why this event was so unusual, you must shed light on the lack of motion after landfall of this strong hurricane/tropical storm.
BTW Cliff Mass is hardly a sceptic


One recent storm highlights the potential consequences of this slowing trend. In 2017, Hurricane Harvey stalled over eastern Texas rather than dissipating over land, as hurricanes tend to do. It drenched Houston and nearby areas with as much as 50 inches of rain over several days, shattering historic records and leaving some areas under several feet of water.

Another joke of research where alleged scientists apply their confirmation biases to draw out the latest fears.
Harvey was stalled by a blocking atmospheric event. It’s called weather and it happens frequently.

However, Harvey gave alarmists another mechanism that they could computer model new disasters; e.g. excessive rain totals, fooding, stalled cyclone allowing high winds to devastate, etc.
All disasters tinkered and tailored into their models.

Another researcher who should never receive government funds.


I want to know who is foolish enough to measure the speed that hurricanes travel, and how do they do it.
That is all.


Hurricane hunter aircraft are special hurricane forecasters who help track hurricanes to predict where they will make landfall so residents of coastal areas can prepare properly, and they help save lives.


Best Track Data is that fiddled with or is it empirical?

Richard Aubrey

Harvey didn’t “stall”. Harvey was blocked. Different mechanism altogether and one that anybody watching the weather that month knew. And it didn’t just stall someplace. It stalled over the Houston area with approx half of its activity still over the Gulf. So, after dumping a load, the winds swung over the Gulf, reloaded, and went ashore again. And again.


The number of hurricanes in 68 years, he didn’t say tropical storms or anything like that, he says only hurricanes can be counted, already sounds to me like too small of a sample to determine anything statistically significant. But then he goes and breaks it down by where, and now I’m sure all his number crunching don’t mean squat. I do congratulate him on using actual numbers of things that really happened, that’s better than the study described in the last paragraph that used only imaginary data, oops, um, model outputs. Who knew, that square root of negative one must mean something in statistics, too.