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This Year’s Atlantic Hurricanes In Perspective

September 27, 2017

By Paul Homewood


The recent spate of hurricanes has inevitably attracted attention and spawned wildly inaccurate headlines, such as “a 1000 year event”, “the most powerful Atlantic storm on record”, “storm of the century”, and even “most deadly storm in history”.

Many climate scientists have also jumped on the bandwagon, to claim that these storms have been exacerbated by climate change.

With Hurricane Maria now weakening and heading north into cooler waters, it is perhaps time to take a rational look at what has actually been happening.

First, let’s look at the two most notable storms:


Hurricane Harvey

When Harvey made landfall at the Texas coast on Aug 25th, it ended the longest period without a major hurricane making landfall in the US on record. The previous one had been Hurricane Wilma in 2005.

With winds of 130mph, Harvey was not an unusual storm in any sense, and Texas is often on the receiving end of major hurricanes (defined as Cat 3 and over). There is usually at least one every decade, but prior to Harvey the last one had been Gilbert in 1988.

However, what made Harvey so catastrophic was that the storm stalled close to Houston for five days, thus dragging in large amounts of moisture from the Gulf, and dumping it all on a relatively small area. In the end, the area around Houston received up to 51 inches of rain in six days.

This stalling of storms, caused by weather blocking patterns, is not unusual, and can be explained by perfectly natural meteorological reasons. For instance, in 1978 Tropical Storm Amelia dropped 48 inches of rain in four days on Medina in Texas.

It has been claimed that warmer ocean temperatures had increased the intensity of rainfall from Harvey, but Texas has seen far worse in the past. During Tropical Storm Claudette in 1979, an incredible 43 inches of rain fell on Alvin in Texas, still a record for the US as a whole.

What made Harvey so damaging was that the rain fell on and around Houston, which has a history of notorious and catastrophic flooding, since it was founded in 1836. The reason is the topology, with the city established at the confluence of the Buffalo and White Oak Bayous, and in the middle of very flat, low lying country.

Damage is worsened because, as the city expanded, much construction took place in flood-prone zones. Subsidence and concreting over of wide areas has served to make matters even worse.



Hurricane Irma

It has been widely, but wrongly, reported that Irma was the “most powerful Atlantic storm on record”.

Irma had 1-minute sustained wind speeds of 185mph, but there have been three other Atlantic hurricanes since 1980 alone, which have been at least as strong – Allen, Gilbert and Wilma in 1980, 1988 and 2005 respectively. Allen was even more powerful, with winds of 190mph.

None of these storms were anywhere near as damaging as the Labour Day Hurricane, which devastated Florida in 1935 with winds of 185mph. This was because the others reached full strength out over the ocean and well away from land.

And here lies the problem in trying to compare today’s hurricanes with those of the past. We have only had comprehensive monitoring of hurricanes in the Atlantic by satellites since around 1980.

Prior to that hurricane hunter aircraft began coverage in 1944, but in the early decades did not enter the eyewalls of the strongest storms, for understandable reasons! Consequently the strength of storms in those times tended to be underestimated. Even then they only provided coverage over about half of the ocean.

It is therefore not possible to say whether there were other storms in the past as powerful as Irma.



2017 Atlantic Hurricane Season

So far this year, there have been four major hurricanes, Harvey, Irma, Jose and Maria. How unusual is this?

Well, as it turns out, not unusual at all. According to NOAA’s Hurricane Research Division, there have been 26 other years with four or more.

The record year was 1950, which had as many as eight. Prior to the deployment of hurricane hunter aircraft, there will have been many more which were missed entirely.

As can be seen, there is no evidence that major hurricanes are becoming more common either. The dip around the 1970s and 80s corresponds with the cold phase of the Atlantic Multidecadal Oscillation (AMO). It is well established that the AMO affects the intensity of hurricanes in this way. According to NOAA, during warm phases of the AMO, the numbers of tropical storms that mature into severe hurricanes is much greater than during cool phases.






Again, when we look at Accumulated Energy (ACE), there are no obvious trends either. The record year was as long ago as 1933.




US Landfalling Hurricanes

Given the lack of coverage prior to 1980, the only reliable way to make long term comparisons is to look at hurricanes which made landfall in the US, where reliable records have been kept since the 19thC.

The Hurricane Research Division has carefully reviewed these records and classified the storms accordingly. They say that there have been 24 hurricanes as powerful or more as Irma.

The decade with the most major landfalling hurricanes was the 1940s, and, as already noted, we have just gone nearly 12 years without one at all, the longest spell on record.






By far the most powerful storm at landfall was the Labour Day Hurricane, followed by Camille in 1969, and Andrew in 1992.

There is an inference that two major landfalling hurricanes in one season, Harvey and Irma, is somehow unusual. This is nonsense, as it has happened on 14 other occasions since 1851, with the first such occasion being in 1879.



What Part Do Sea Temperatures Play?

Certain climate scientists have claimed that warmer sea surface temperatures have played a major role in intensifying this year’s hurricanes. While this is superficially an attractive idea, the historical record outlined above suggests that things are not as black and white.

Hurricane experts maintain that sea surface temperatures in the tropical Atlantic, Caribbean, and Gulf of Mexico are high enough every year to potentially spawn catastrophic hurricanes.

There are, however, many, and extremely complex, natural meteorological factors which determine the intensity and frequency of hurricanes. Things like wind shear, the presence of drying influences such as pockets of Saharan dust, the speed of hurricane tracks and their direction.

Given the recent dearth of major Atlantic hurricanes, it is extremely naive to single out one factor, sea surface temperatures, to put the blame on.

I have already mentioned the influence of the AMO. It is perhaps worth pointing out that hurricane droughts in the Atlantic during the cold phase of the AMO are directly linked with droughts in the Sahel and beyond to India.

Unfortunately the world’s weather is not perfect, and, as one part of the world suffers from hurricanes, another benefits from welcome rainfall.


Hurricanes In The Past

As already noted, it is difficult comparing storms of today with those of the past. Whereas we now have satellites and hurricane hunter aircraft to provide comprehensive monitoring, not very many years ago all we had was ground instruments.

When a very strong storm appeared, anemometers were usually destroyed before the strongest gusts could be recorded. The same often occurred with other equipment.

Moreover, the highest wind speeds in a hurricane only occur in a relatively small part of the eyewall. The odds of having reliable recording equipment at the exact part of the coast where this occurs, are actually pretty slim, particularly in earlier decades. As a consequence the top speeds of hurricanes were very rarely actually measured.

What we can compare though is the impact they have had.

You could write a book about the devastation brought about by hurricanes in the 19th and 20thC. Hurricanes such as the one which destroyed Galveston in 1900, leaving up to as many as 12000 dead.

Or the Great Miami Hurricane which wiped Miami off the map in 1926. Florida was also on the receiving end of two other devastating storms around that time, Lake Okechobee in 1928 and the Labor Day Hurricane in 1935.

The sort of death tolls seen in those days would be beyond the imagination of people these days. And there is a very good reason – resilience.

Buildings and infrastructure are now better built to withstand storms, and warnings and evacuation procedures more effective.

Hurricanes always have been, and always will be, deadly and destructive. No number of wind farms or solar panels will alter that fact. We would be much better off investing money on protecting vulnerable regions, rather than on trying to make hurricanes go away.

  1. Ian Magness permalink
    September 27, 2017 9:52 am

    Great summary Paul – sane and factual.
    Definitely one to “cut out and keep” and show to those less well-informed (who will, of course, neither read nor believe it, but at least we can keep trying).

  2. HotScot permalink
    September 27, 2017 9:55 am

    Excellent summary. Thank you Paul.

  3. geordie stuart permalink
    September 27, 2017 9:59 am

    Brilliant . Homewood should be made a member of Lord Deben’s Climate Change Committee Scam in the HOL .

  4. September 27, 2017 11:06 am

    Reblogged this on Tallbloke's Talkshop and commented:
    A rational look at recent severe weather events, which have been seized on by disaster-starved climate alarmists to push their pre-conceived agendas.

  5. September 27, 2017 11:30 am

    A great piece of work which has convinced at least two friends of mine that hurricane hysteria is unwarranted

  6. September 27, 2017 11:37 am

    >It has been widely, but wrongly, reported that Irma was the “most powerful Atlantic storm on record”>

    No, sorry, but it is a true statement but maybe not the clearest. Irma is the most powerful Atlantic [Ocean] storm on record. That was the point of their statement. Hurricanes Allen, Gilbert and Wilma reached their intense levels while in the Caribbean Sea …which is not the Atlantic Ocean.

    • September 27, 2017 4:36 pm

      NOAA’s Hurricane Research Division are absolutely clear that the Caribbean is within the Atlantic, and all of their hurricane listings confirm that.

      Geographically the Caribbean is a sea within the Atlantic Ocean

  7. NeilC permalink
    September 27, 2017 11:45 am

    I don’t understand why they keep the mantra going about Irma being the worst storm ever.

    The Carribean Islands did catch the brunt of it and was probably a Cat4/5.

    Key West, FL also suffered badly but Key West bouy only showed sustained 61Kts/gust 78Kts.

    On mainland Florida, landfall was at Naples with highest wind speed only 56/72Kts at 1800Z (not even a Cat 1 on the Saffir/Simpson scale land based observations),not estimated wind speeds from recon aircraft. Interestingly the sustained wind at Naples at 1700Z was 5Kts, the eye of the storm.

    We get lied to all the time by the green blob and MSM journalist who can’t be bothered to check the facts.

    • jim permalink
      September 27, 2017 12:37 pm

      Neil C, I agree completely. As I have a property in Fort Myers I was watching Irma’s progress with interest. As soon as the eye hit Marco Island, just south of Naples, the southern wall collapsed completely. None of the ground weather stations recorded wind speeds above ‘tropical storm’ levels, not as high as Cat1.
      By the time it had trundled up the US41 to Fort Myers it was so weak it got diverted, just like most weather events, north east by the Caloosahatchee river. Our house had one pool netting panel ripped and some wall climber plants blown over, power restored in 24 hours.
      Sea water surges were half the minimum forecast along the Gulf coast.
      The worst effected areas in SW Florida were inland areas , built on reclaimed swamp land which flooded because of rainfall.
      I came to the conclusion days before, that the NHC deliberately put out the most fear inspiring messages possible to justify politicians making many hundreds of thousands of people compulsorily leave their homes. The mandatory evacuation orders covered where our house is located.
      As I have said before the ‘3 little pigs’ fable tells it all. We have lost all common sense. Compare the effect of Irma/Maria on impoverished Caribbean islands with those of Bawbag on Glasgow. Bawbag did have sustained ground speeds of over 100 mph. As did the hurricane a few days later just after hogmaney 2012 , but the Scots ignored this one as a ‘wee wind’.
      As Paul says , the methodology has changed so much in recording these events. The majority of past hurricanes would be ‘off the scale’ if they could be reevaluated using today’s techniques for capturing fleeting maximums.

      • Joe Public permalink
        September 27, 2017 9:30 pm

        ” … Sea water surges were half the minimum forecast along the Gulf coast.”

        Are you sure? I’ve not seen that reported by MSM on eastern side of the pond.


    • Sheri permalink
      September 27, 2017 1:17 pm

      Because every single storm of any size is “the worst ever”. That is the ONLY line the news uses now. They have no sense of reality or what anything they say means or what reactions it causes in others. They don’t care. They are the screaming, hysterical chickens shouting the “sky is falling” and believing that people will never catch on to the sun shining and the rain stopping. All they understand is pathological hysteria. I suppose when one dumbs down a population far enough, you are to expect this. The media comes from the most far left—read as most uneducated–on the planet and believe that everyone is as dumb as they are. They have never seen the real world and reality terrifies them. I don’t see any fix any time soon. People still predict the end of the earth—we dodged a bullet Sept. 23rd, according to some. Pain and doom sell. People are drawn to them. It’s who we are.

  8. September 27, 2017 1:05 pm

    Wikipedia looks at the Irma ‘records’ (or not) here.

    In terms of ‘Most intense landfalling hurricanes in the Contiguous United States (Intensity is measured solely by central pressure)’ Irma is 7th on the Wiki list.

    Of course there are various other categories of record that can be and are put forward.

  9. September 27, 2017 2:03 pm

    Reblogged this on Climate Collections.

  10. RAH permalink
    September 27, 2017 5:03 pm

    Never ending hype. 11 years 10 months with no strike on the lower 48 is due to luck. But a couple of supposed Cat 4s come ashore and another strikes US territories and it’s due to climate change. Who in their right mind would buy that bull?

  11. johninboston permalink
    September 27, 2017 7:03 pm

    Maybe I read this wrong, but the statement that says, “There is an inference that two major landfalling hurricanes in one season, Harvey and Irma, is somehow unusual.” Actually, it was three, if you include Maria, which hit Puerto Rico (a territory of the U.S.) and they’re still recovering. But the rest of the article is spot on.

    • RAH permalink
      September 27, 2017 7:32 pm

      Guam is a US territory. So during the 11 year and 10 month hiatus if it had been hit by a typhoon do you think it should have counted?

      • Sheri permalink
        September 27, 2017 9:18 pm

        According to Wiki, yes, it is considered part of the US as is Puerto Rico and the US Virgin Islands.

        It depends on who is speaking whether or not they are counted, it seems. I’m sure the climate change people would count them!

      • RAH permalink
        September 27, 2017 9:50 pm

        They are protectorates and not states. Thus they have nonvoting or very limited voting representatives in the House of Representatives. Kind of a fine point really. But it was clear all along that the hiatus or “hurricane drought” referred to the lower contiguous 48 states not only leaving out territories but also the states of Alaska and Hawaii.

      • Sheri permalink
        September 28, 2017 2:10 am

        RAH: “Part of the United States” and “are states” are two different things, yes. Washington DC is not a state, has only one representative with limited voting, yet if a hurricane hit Washington DC, I’m sure that would have counted. If we count only contiguous states and not Hawaii or Alaska, then omitting Guam would make sense. As I said, it depends on who is speaking and what their view is whether or not these things count.

      • RAH permalink
        September 28, 2017 6:45 am

        A Hurricane could not get to the DC without passing over either Virginia or Maryland.

      • Sheri permalink
        September 28, 2017 1:48 pm

        RAH: I’ll leave out the “hurricane strength” only when the storm goes over DC possibility (yes, I could be a government employee with ease) and concede that I really don’t care in the least about any of this. I’m sorry I dropped in.

    • September 28, 2017 9:16 am

      NOAA always count “Continental US Landfalling”, John

      • Sheri permalink
        September 28, 2017 1:49 pm

        Thank you.

  12. RAH permalink
    September 27, 2017 7:34 pm

    BTW Tony Heller has posted a youtube video showing the damage to the Puerto Rico’s wind and solar power facilities. Pretty devastating.

    • Joe Public permalink
      September 27, 2017 9:35 pm

      Thanks for sharing.

      As you mention, the facilities shown have been smashed to smithereens.

      • RAH permalink
        September 27, 2017 9:55 pm

        Renewables only makes up 2% of the total generating capacity, the rest comes from coal and gas fired generating stations. Not that it matters much because even if those renewable facilities had not been mangled the real challenge before them is getting transmission grid up and running to get the power to where it’s needed. They are in for a long period of hardship.

  13. shivering permalink
    September 29, 2017 3:54 pm

    “None of these storms were anywhere near as damaging as the Labour Day Hurricane, which devastated Florida in 1985 with winds of 185mph. ” Later you mention 1935. Another excellent article.

    • September 29, 2017 5:26 pm

      Thanks for spotting the typo- it should of course be 1935

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