Study: a ‘statistically significant downward trend since 1950 exists’ in hurricane landfalls

This is going to rattle some cages, while at the same time vindicating Dr. Roger Pielke Jr. A new study in Geophysical research Letters studies hurricane activity in the Atlantic concludes that a “statistically significant downward trend since 1950 exists”.

An Energetic Perspective on United States Tropical Cyclone Landfall Droughts

Authors Ryan E. Truchelut, Erica M. Staehling


The extremely active 2017 Atlantic hurricane season concluded an extended period of quiescent continental United States tropical cyclone landfall activity that began in 2006, commonly referred to as the landfall drought. We introduce an extended climatology of U.S. tropical cyclone activity based on accumulated cyclone energy (ACE) and use this data set to investigate variability and trends in landfall activity. The drought years between 2006 and 2016 recorded an average value of total annual ACE over the U.S. that was less than 60% of the 1900–2017 average. Scaling this landfall activity metric by basin-wide activity reveals a statistically significant downward trend since 1950, with the percentage of total Atlantic ACE expended over the continental U.S. at a series minimum during the recent drought period.

Plain Language Summary

The 2017 Atlantic hurricane season has been extremely active both in terms of the strength of the tropical cyclones that have developed and the amount of storm activity that has occurred near the United States. This is even more notable as it comes at the end of an extended period of below normal U.S. hurricane activity, as no major (category 3 or higher) hurricanes made landfall from 2006 through 2016. Our study examines how rare the recent “landfall drought” actually was using a record of the estimated total energy of storms over the U.S., rather than prior methods of counting hurricanes making U.S. landfall. Using this technique, we found that 2006–2015 was in the least active 10% of 10 year periods in terms of U.S. tropical cyclone energy but that several less active periods had occurred in the last 50 years. The 2006–2016 drought years did record the lowest percentage of storm activity occurring over the U.S. relative to what was observed over the entire Atlantic. This finding is further evidence for a trade-off between atmospheric conditions favoring hurricane development and those that are most favorable for powerful storms to move towards the U.S. coastline.

Full paper (paywalled)

Dr. Roger Pielke Jr’s Hurricane Drought Graph:

The end: It’s over – 4324 day major hurricane drought ends as Harvey makes landfall at Cat 4

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Tom Halla
December 9, 2017 6:12 am

The green blob will consider this study doubleplus ungood crimethink.

Steve Case
Reply to  Tom Halla
December 9, 2017 6:22 am

The green mafia will ignore it.

Steve Case
Reply to  Tom Halla
December 9, 2017 6:41 am

 A Google Search Hurricane in the news turns up the same old same old:

This Year’s Hurricane Season Was Intense. Is It A Taste Of The …
NPR-Dec 4, 2017
There were huge hurricanes and brutal seasons before climate change. But scientists now say the oceans are warmer; the tropical Atlantic and Gulf of Mexico were especially so this year. “So these storms were indeed exactly what we’ve been worrying about with respect to climate change,” Trenberth says, …

2018 will be another busy hurricane season, UK-based experts predict
Sun Sentinel-Dec 7, 2017
The Atlantic hurricane season officially ended a week ago, but already the predictions for next season are starting to emerge. And like dark clouds on the distant horizon, they are not reassuring. The 2018 season will be another above average one, according to a forecast issued Thursday by Tropical Storm …

Later today I’ll search again – maybe on Monday there might be something. “Reporters” like to enjoy their week ends you know.

Steve Keppel-Jones
Reply to  Steve Case
December 11, 2017 11:28 am

“before climate change”? That’s pretty funny… how long ago was that, exactly?

Gunga Din
December 9, 2017 6:58 am

The Weather Channel did a “documentary” on this years hurricane season.
They called it “Hurricanes 2017, Cruel and Unusual”.

Reply to  Gunga Din
December 9, 2017 9:57 am

I have a hunch the show did not feature this graph that Colorado State maintains, nor mention it was only the North Atlantic Basin that had a “cruel” season. (A busy year, but not unusual.)

Gunga Din
Reply to  Windsong
December 9, 2017 11:52 am

Probably right.
I sometimes wonder if TWC has a Department of Hyperbole and Alliteration.

Pop Piasa
Reply to  Windsong
December 9, 2017 1:09 pm

Just in quest of higher viewership via sensationalism. Pretty typical of any media outlet these days.

Where can they push it from here?

Dave Fair
Reply to  Pop Piasa
December 9, 2017 2:19 pm

Man’s imagination knows no bounds, Pop. Take any religion … please.

Dave Fair
Reply to  Pop Piasa
December 9, 2017 2:20 pm

I regret the snark, everyone.

Reply to  Windsong
December 9, 2017 3:12 pm

Gunga Din

December 9, 2017 at 11:52 am

Alliteration: –
Amazing apparently atypical Air-movements Activate Anthropogenic Activists’ amiss Amazement, apparently, astonishingly, amusingly – abusing alliteration – ahh, allegedly.

Hoping that is good enough for a Saturday evening when red wine has been imbibed.
A bit.

Reply to  Gunga Din
December 9, 2017 5:05 pm

“Cruel and Unusual” was the term I used when lunch was brought in for the third day of my jury duties.
The judge was on a mission to judge the loser, she (afterward) made no bones about it, he took the cowards way out by driving into the side of a building which put him in hospital, thus (again) avoiding his destiny.
Murder in the first. Cook County, Illinois.

December 9, 2017 7:16 am

Landfalls are a matter of weather/chance. No drought of Atlantic hurricanes seems to exist. Lets not cherry pick like agw fanatics.

Reply to  JimG1
December 9, 2017 7:36 am

Before I look at the archive, jim, tell me that it ONLY includes Cat 3 and higher.

Reply to  ClimateOtter
December 9, 2017 7:45 am

Doesn’t say. If you know something, take a look and tell me.

R. Shearer
Reply to  JimG1
December 9, 2017 7:44 am

Yes, and sometimes luck is with you.

The Original Mike M
Reply to  JimG1
December 9, 2017 7:51 am

Are those all land falling US hurricanes? (& cat 3 or above as CO asked?)

Alan Watt, Climate Denialist Level 7
Reply to  JimG1
December 9, 2017 7:55 am


I was about to make a similar comment — I don’t understand the significance of this study to the “global warming causes more extreme weather” debate one way or the other.

I have no expert knowledge of hurricanes, but clearly if a hurricane never forms it cannot make landfall anywhere. The interesting thing to know is the rate of tropical storm formation and the strength distribution. But I doubt we have reliable data for that prior to the satellite era.

Another question I have is whether the record starting at 1900 is adequate to distinguish a trend from background variability. Another question we don’t have the data to answer. Was storm frequency and strength greater during the Medieval Warm Period or the Little Ice Age? That might be really interesting to know but I don’t think we have any idea.

What might be interesting is to construct the same chart for other countries around the Atlantic hurricane basin. What does it look like for Puerto Rico or Cuba?

Is the 2017 hurricane season predictive for the future, or is the record-setting 4324 days prior? I have no idea. Betting on roulette has better odds.

Reply to  Alan Watt, Climate Denialist Level 7
December 9, 2017 8:13 am

The biggest question in my mind on historical charts, the farther one goes back in time, is the accuracy of the reporting. Less people=less observers plus communication etc. Then there is the bias of those compiling the data as well. But with the data I have shown, at least, I see no hurricane, nor tropical storm drought and continue to believe that chance and such unknown factors, historically speaking, play a major roll in landfalls. So nothing here to see.

Michael Jankowski
Reply to  JimG1
December 9, 2017 9:13 am

Sure, there’s no “drought of Atlantic hurricanes.” The “drought” was major hurricanes making landfall.

ALL hurricanes “are a matter of weather/chance.” The same is true for all weather events.

We were told to expect more intense and frequent hurricanes (which was changed to possibly less frequent but more intense hurricanes as they wiped egg off of their faces). We were told to expect the season with Katrina, Rita, etc, to become a regularity. We were told damage from weather events like hurricanes were increasing and that it was due to global warming.

This isn’t “cherry-picking.” It’s refuting claims made by Mann, Trenberth, and their ilk.

Reply to  JimG1
December 9, 2017 9:53 am


only remotely valid historical data is land-fall data. We don’t know how fast wind blew in mid-Atlantic in 1609. But now we know he eye-wall speed from whatever hurricane hitting or not hitting anything.

Reply to  JimG1
December 10, 2017 5:44 am

The reason why Landfalls are used is to compensate for improvements in observability.

December 9, 2017 7:30 am

Year ago a oceanographer at University of Miami had a large grant looking at Florida Current/ Gulf Stream mass transport. As most here know the earth is always trying for an energy balance between the tropics and the poles. The hypothesis was that were two primary transport mechanism, tropical cyclones and boundary current transport. If one was not happening then it appeared obvious that the other system had to make up for it. Well it didn’t turn out that way. Over the time period of the study mass transport in the current system didn’t fluctuate very much nor at the time were there many tropical cyclones. The new hypothesis as I understood it was that energy built up in the tropics but only periodically did either tropical cyclones or currents system move the heat energy poleward, at least in the Atlantic.

F. Leghorn
December 9, 2017 7:46 am

“This will rattle some cages” is exactly what is wrong with science today. Science isn’t supposed to be able to “rattle cages”. It may well surprise you and even astound you, but make you upset? Only if the data gores your pet ox. And if you’re in it to prove your pet theory then you are in it for the wrong reasons.

Joel O’Bryan
Reply to  F. Leghorn
December 9, 2017 8:18 am

Climate change science ceased being science and turned to pseudoscience with the 1995 Second AR human attribution statement. And it’s Still pseudoscience as the politics, reputation, and money don’t allow them to walk it back.

Reply to  F. Leghorn
December 9, 2017 11:15 am

These days people get upset when you point out that their forecasts of imminent doom were incorrect.
Still trying to wrap my head around that insane mentality.

Stevan Reddish
Reply to  menicholas
December 9, 2017 12:30 pm

I imagine their thinking is that the wrongness of their prediction was caused by merely temporary factors that will soon change to their predicted direction.

But…If they understand the factors driving the weather so well, they should have predicted this period of non-compliance with the imminent doom prediction.


December 9, 2017 7:47 am

I agree.

Atlantic Hurricanes are NOT becoming more frequent or more intense – in fact, the opposite is true.

I assembled these graphs in 2005.


Updated August 2005

December 9, 2017 7:54 am

Tell that to the bond ratings groups setting up risk metrics based on the opposite alt universe created by Obama operatives as a lasting legacy of policy fraud.

Bruce Cobb
December 9, 2017 7:57 am

See? That’s climate change, and is consistent with the models. Told ya.

December 9, 2017 7:57 am

What a breakthru – science examines hurricane data and reports the obvious – something anyone with two eyes can see. Hurray!

Gary Pearse.
December 9, 2017 8:07 am

Actually, I predicted a strong active season to return in a few years 3-4yrs ago here on WUWT. In the midst of the crowing about no landfalls I said it was a mistake to overdo this and rather, with the 65year natural cyclic variation in climate we should be predicting another like the mid 1950s. This was to get ahead of the herd. Alas, no one thought it a good idea. I also predicted thehistorians response of the climateers and the MSM. Sigh! I wish I could locate one of the posts – I did this a couple of times during the rejoicing.

Gary Pearse.
Reply to  Gary Pearse.
December 9, 2017 8:09 am

Dang refactor not ‘historians’ but ‘climateers’.

December 9, 2017 8:31 am

That’s two more scientists crossed off the Mann-Lew Xmas card list.

Reply to  Phillip Bratby
December 9, 2017 10:45 am

Phillip Bratby

Ze dissent ees noted. Ve vill be concocting ze appropriate response. It vill be in ze form of a peer reviewed personal attack on ze author off zis propaganda!

Mann et al.

December 9, 2017 11:01 am

Klotzbach and Gray came up with an interesting chart back in 2008.comment image
It’s in – page 34.

Cat 3-4-5 US landfall hurricanes appeared to be be more associated with global cooling than with global warming.

It could be that they just tend to make land-fall more during global cooling, or it could be that some other factor was at play which happened to coincide with two particular periods, one cooling one warming, or maybe it’s an AMO thing. But if it is a global cooling thing, and if we are now in a global cooling period, then maybe the US can expect more 3-4-5 hurricanes. Hard to know, because it looks like hurricanes are hard to forecast (K&G’s 2008 forecast was I think well off the mark).

As far as I am aware, they haven’t mentioned the hurricane-cooling link since (peer pressure??). But the 2008 chart was from recorded data, it wasn’t an opinion or a forecast.

Reply to  Mike Jonas
December 9, 2017 11:21 am

Since hurricanes represent a large net poleward movement of energy from the tropical oceans, it makes sense that more hurricanes equals global cooling, relative to less hurricanes…all other factors being equal. Now, all other factors are never equal, but still…

Reply to  Mike Jonas
December 10, 2017 9:29 am

Cyclones depend upon differential temperatures, not absolute temperatures. Which is why you can get massive cyclones on chilly Mars. It may well be that cooler periods have a greater temperature differentials between high and low latitudes.


Reply to  ralfellis
December 11, 2017 8:28 am

Hurricanes are big @#&%! heat engines – just like most active weather. The climate change climastrologists either never took or flunked thermodynamics.

December 9, 2017 11:09 am

The really crazy part is that, with the exception of Puerto Rico, the US has not had a direct hit by a really powerful Hurricane, since Katrina hit the area East of New Orleans.
And that one did not hit a particularly densely populated portion of the region with it’s most intense effects.
And I cannot even recall when the last time a Cat5 storm and surge hit a major metropolitan area directly.
Most people alive in the United States today have no idea how bad it can, and someday will, be.
At some point a truly awful storm will hit a major population center, and may even do so with little advanced warning.
We saw during the preparations for Irma how chaotic it can be, but really only had a glimpse. The long lead time spread out the evacuation over many days, and a lot of people knew that they did not have to go anywhere and so did not.
We have seen in previous evacuations how bad one of them can be, when hundreds of thousands of people are stranded in vehicles with no where to go and fuel tanks empty.
Seriously, we in the US remain very fortunate.
A look at the history of powerful hurricanes gives a glimpse, and that is really the only clue even those in the know have of what is someday to come.

Reply to  menicholas
December 9, 2017 3:22 pm

Andrew 1992 was the last Cat 5. I saw the damage path first hand. There is no way that words can describe the destruction, except that it reminded me of photos of Hiroshima. Look up the photos.
Andrew was initially called a Cat 4 but all the surface anemometers were destroyed. It was the post-storm damage assessment that caused the final reports to make the shift from Cat 4 to Cat 5.
Wilma 2005 was the last major hurricane to make US landfall.

Reply to  bw
December 10, 2017 9:16 am

Yes, I was in Florida when Andrew hit, and in fact was in the plant nursery bidness at the time. Homestead was one of the centers of our industry. I too saw the destruction.
But Homestead and Florida City were not huge metropolitan areas. Had that storm hit Miami, we would have an example of what I am referring to.
Ditto Katrina. It did not hit a city with the eyewall and storm surge.
A review of how far inland Katrina’s surge travelled gives a truly shocking look at what could happen.
6 miles inland it travelled in many areas of Mississippi, and up to 12 miles near bays and rivers. It was a 27′ high surge. People miles from the ocean were drowned by the sea.
Some islands were virtually erased, and the beaches were levelled.
In the area of the landfall of the right front quadrant, 90% of structures within half a mile of the coast were destroyed.

Reply to  menicholas
December 9, 2017 3:31 pm

But with electric vehicles i6t doesn’t matter if the fuel tanks are empty.

Mods – just in case – /Snarc of a high order. No power; no electric power. No car movement. At the mercy of the storm – or hurricane!
And how!


Dave Fair
December 9, 2017 11:54 am

Brace yourselves, people. This paper may allow the CAGW-ers to assert fewer hurricanes as proof of global warming.

Stevan Reddish
Reply to  Dave Fair
December 9, 2017 12:18 pm

If they do, we can say: One more item we can add to the list of Reasons Global Warming is Beneficial.


Reply to  Stevan Reddish
December 11, 2017 8:31 am

No, they will just claim that mankind is interfering with the natural seasonal migratory patterns of BTUs.

December 9, 2017 2:38 pm

This sort of report will not be well received at Climate Central. It is well known there that US Hurricanes are not only getting stronger but are also getting more frequent, directly caused by rising CO2 levels. Contrary evidence is not welcome and will be officially repudiated and ignored.

December 9, 2017 3:07 pm

The NHC claim that Harvey 2017 was Category 4 are mostly based on aircraft radar, with some other inputs into their real time forecasts and discussions. Then a model is used to estimate surface winds.
That’s not data, it’s an extrapolation, and the NHC is wrong. Real time sustained wind data from surface stations and offshore buoys with anemometers about 10 meters above the surface always show winds significantly lower than the NHC claims.

Actual sustained surface winds measured at 10 meters by anemometers and offshore buoys show that Harvey was mostly a Category 1 storm at landfall with a single band of Category 2 that lasted about 4 hours.
Photos of damage are entirely consistent with the winds measured by the surface anemometers and the Saffir-Simpson scale definition for a Category 1 tropical cyclone.

Harvey is not an isolated case, the NHC has been doing the same thing for years, with the last few years being increasingly egregious. Irma was not a major hurricane for the same reason. Surface data say Irma was not even a Category 1 at Florida landfall. Data and photos say is was a tropical storm. Many photos of damage are biased to show localized damage that is not typical of the surrounding area. Post-hoc photos of wider areas showing the general amount of damage in the path of the storm should be used to characterize which number on the Saffir-Simpson scale is the best representative of that storm.
Post-hoc damage assessment invariably confirms the real time sustained wind data recorded by the surface anemometers because that is how the Saffir-Simpson scale was created, by definition.
Maria was Category 1 at Puerto Rico landfall.
Anyone who watches these storms in real time will say the same in regard to NHC hyping the danger for years. More detail in the August link.

Reply to  bw
December 9, 2017 3:39 pm

May I suggest that, whilst you are surely scientifically correct, some sympathetic comment about those dealing with the on-the-ground damage caused by these winds – whatever designation – would be seen as reasonably appropriate.
Something like –
Whatever the actual numbering or designation given to these winds, we do hope that those affected make a quick recovery from the devastation visited upon them. We feel in our hearts for those who lost relatives or friends, and those injured during this horrible experience.

Or similar – do use your wording – it will be better than my first effort here, I have no doubt.


Reply to  bw
December 10, 2017 9:38 am

I weathered Irma in my house.
I have some amazing video of the winds. By the time the eye passed over my house, it had travelled over more than 100 miles of land.
It was definitely a hurricane at landfall.
Not sure if you live in Florida…I suspect not.
I know people who were trapped in what was left of their homes in Collier County for over a week after the storm passed.
Collier county was devastated.
In area east of Fort Myers, winds over tropical storm force blew for over 24 hours.
I agree the storm was not as bad as many were led to believe, but given the damage, it just goes to show what will happen when a full strength cat 5 hits directly.
As it was, loss of life was not huge, and that is because wind kills relatively few people, even when the building they are in is levelled. People just manage to find places to hide it seems
Another reason it was not a huge killer and mostly caused flooding and tree damage is because of building codes having been beefed up in recent years, and most of the homes in this area are relatively new.
I had a small tornado pass within about 25 feet of my house, and had only damaged roof tiles where objects hit it. My house is a virtual fortress.
But anyone outside would have been dead many times over.
I pulled trees limbs and branches out of the ground that were in the sand as much as 18′ or more.
Hundreds of smaller branches from a Norfolk Pine were into the ground like spears about 4-6″.
It was unsurvivable to anyone outside when the eyewall passed. Debris from trees and shrubs filled the air.
I watched fronds from royal palms (got it on video) fly by at what I could easily tell was fast highway speed.
Those things are as long as a bus and weigh over 50 pounds when they are green. Maybe 100 lbs. Not really sure, but they are heavy and large.
It was amazing to watch. And listen to.
The winds in those storms are in bands just like the rain. You can hear the larger gusts coming from blocks away, by the sound of the wind in the tall trees. It was almost identical to the sound of an airliner landing right over your head. I heard the gusts getting closer and closer, and then hit. After a while, I knew when the gusts were coming about 30-45 seconds in advance.
I will not stay for anything predicted to be over 130 mph in the location I am…and only then in my own house or a shelter.
The worst part for most of us here in SW Florida was losing power, as I already knew from 2004 and 2005.
I have that covered now…will not lose power again, or have any tree close enough to the house to fall on it. Ever.
In the future, my preparations will consist mainly of cutting limbs and branches from trees.
Chop them back to skeletons is the best thing to do.
Irma was most definitely a hurricane, even over 100 miles from where it came ashore.

Reply to  menicholas
December 10, 2017 9:42 am

Sorry, that should read 18″, not feet.
An abject going fast enough to penetrate packed sand for 18″, I can only imagine what it would do to flesh.

Dr. S. Jeevananda Reddy
December 9, 2017 6:15 pm

1. Hurricane Season: tropical storms +hurricanes and hurricanes during 1913 to date present a normal distribution with peak at 10th September varying between 1st June to 30th November — peak 90 & 50, respectively

2. major hurricanes, hurricanes &U.S. land falling hurricanes presented a 60-year cyclic variation — around 50 the peak start declining phase and reached to the peak currently — U-shape

Truncated data series invariable present misleading inferences, ifthe data series follow cyclic variation.

Dr. S. Jeevananda Reddy

Patrick MJD
December 9, 2017 7:50 pm

How inconvenient. BTW, in the image on the thread header at the main WUWT page, the hurricanes are swirling the wrong way. Al Gore had it right don’t you know.

December 10, 2017 1:11 am


Two of Hollywood’s greatest climate scientists weigh in with their expert opinions…

December 10, 2017 9:45 am

I do not know anyone who denies that there are climates.

December 10, 2017 9:22 am

The graphs of strong hurricanes and cyclone by Dr Ryan Maue also suggest a diwnward trend since the early 90s.
comment image

December 12, 2017 6:41 am

Did anyone notice the pea missing from the “plain language summary”?

The abstract mentions a ” a statistically significant downward trend since 1950, with the percentage of total Atlantic ACE expended over the continental U.S. at a series minimum during the recent drought period.”

That’s a 66-year long trend — a major finding of the paper. Perhaps the major finding.

No mention of this in the “plain language summary.” It’s not news fit for peons.

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