Skip to content

Is Irma The Most Powerful Atlantic Storm?

September 7, 2017

By Paul Homewood





There seems to be a lot of disinformation around about Irma being the “most powerful Atlantic Ocean storm in recorded history” with sustained winds of 185 mph, such as the Telegraph above. I also heard the same comment on ITV News yesterday.

As I pointed out yesterday:

Four other storms have had winds as strong in the overall Atlantic region but they were in the Caribbean Sea or the Gulf of Mexico, which are usually home to warmer waters that fuel cyclones.

Hurricane Allen hit 190 mph in 1980, while 2005’s Wilma, 1988’s Gilbert and a 1935 great Florida Key storm all had 185 mph winds.

In other words, there have now been four hurricanes as strong or stronger since 1980, about one every decade, and certainly nothing like the “unprecedented” impression left by the headlines.

And as we know, prior to Allen in 1980, we had very little in the way of measurements in mid ocean.

A closer look at the Labour Day Hurricane of 1935, widely acknowledged to be by far the most powerful storm to hit the US, emphasises this fact.

According to HURDAT:

The Labour Day Hurricane was the strongest hurricane to ever make landfall in the United States, based upon its central pressure of 892 mb. The maximum sustained winds at landfall in the Florida Keys are estimated to have been around 185 mph.

And as Chris Landsea’s reanalysis highlighted, wind speeds were probably even higher, up to 164 kt, or 189 mph:


Wind speeds were almost certainly even greater offshore prior to landfall, but in those days there was no way to measure them. Any anemometers in the area would have been destroyed in such high winds.

Therefore meteorologists relied heavily on measurements of pressure, and it is this which casts suspicion on claims about Irma.

If we look again at the five hurricanes listed above, we find:

mph Central Pressure hPa
Labour Day 185 892
Allen 190 899
Gilbert 185 888
Wilma 185 882
Irma 185 914

Wind speeds don’t always correlate exactly with pressure, but pressure is usually a pretty good guide.

And we can see that Irma is not in the same league as the others.

The wind speeds estimated for Irma may be right, but if so it would indicate that they were underestimated for the other storms.


Meanwhile the early indications are that Irma is gradually losing strength, now down to 175 mph.

PHOTO: Hurricane Irma forecast track as of 2 p.m. Sept. 6, 2017.


But the models still have little idea about where it is heading.


PHOTO: Hurricane Irma spaghetti models as of 2 p.m. Sept. 6, 2017.

  1. September 7, 2017 10:38 am

    Is this about the definition of ‘Atlantic Ocean storm’?

    • September 7, 2017 11:02 am

      According to Accuweather: ‘Irma had been tied for the second-strongest hurricane ever recorded in the Atlantic basin in terms of wind speed and remains the strongest hurricane ever recorded outside of the Caribbean Sea or Gulf of Mexico.’

      However, as PH has noted, the pressure data tell a different story and ‘ever recorded’ is subject to the quality of the instruments available at the time of any given event.

  2. September 7, 2017 10:48 am

    Reblogged this on Climatism and commented:
    “And we can see that Irma is not in the same league as the others.”

    MORE sane and measured ‘scientific’ analysis from Paul Homewood. Refreshing, amongst the diatribe of alarmist speculation and theorising from the usual climate ambulance chasing suspects.

  3. Jack Broughton permalink
    September 7, 2017 11:41 am

    The underlying issue is that the world’s “Greenists” have been badly shaken by Trump and are now frantically publishing anything that will keep their agenda in front of people: they are truly masters of the craft! DNV-GL a so-called independent consultancy have just published their review of world energy up to 2050: beautifully put together document but the pretty graphs and graphics are based on some almost unbelievable science.

    They assume, with little comment:
    1. That 0.1% of the world’s land area will be covered with PV generators – this would increase the worlds albedo by about 2%; far more than the theoretical incorrect and totally un-measurable contribution from CO2.
    2. World energy usage will peak at 240 EJ /y by 2030, only 7% increase on present. The developing world can stop developing!
    3. China’s coal usage has already peaked, while India will peak soon.
    4. CCS will be available at $74 / tonne CO2 by 2020.
    These and lots of other improbable assumptions are then used to produce massive reports for use by the gullible.
    The GIGO concept seems to be lost on modern economic and technical mathematical modellers, any hypothesis can be used without much questioning.

    My solution would be to confiscate the spreadsheets from these groups and make them examine the science rather than predict reams of hypothetical outcomes from bad science.

    • HotScot permalink
      September 7, 2017 12:07 pm

      I could have got a similar ‘Spaghetti Model’ had I given my 2 year old granddaughter a map and some crayons.

      Tragically, some scientist will take credit for predicting the single ‘correct’ path of Irma.

      • HotScot permalink
        September 7, 2017 2:03 pm


        It wasn’t real enough to stop scientists making wacky predictions because they can waste their time fiddling with a spreadsheet.

    • HotScot permalink
      September 7, 2017 12:11 pm

      “My solution would be to confiscate the spreadsheets from these groups and make them examine the science rather than predict reams of hypothetical outcomes from bad science.”

      In some ways it’s a shame the millennium bug was fictitious.

      • quaesoveritas permalink
        September 7, 2017 12:41 pm

        What makes you say that?
        As far as I am concerned in was real.
        The only reason a lot of computer systems didn’t fail was a lot of work was put into avoiding it.

      • HotScot permalink
        September 7, 2017 2:05 pm


        Whoops…….!! wrong comment answered.

        It wasn’t real enough to stop scientists making wacky predictions because they can waste their time fiddling with a spreadsheet.

      • quaesoveritas permalink
        September 7, 2017 2:43 pm

        Some of the predictions might have been fictitious but the “bug” itself was not.
        The pharmaceutical company I worked for, had to change it’t operating software, and spend a lot of man hours transferring data from the old system.

      • HotScot permalink
        September 7, 2017 8:42 pm


        I suspect you miss my point, or I made it badly, probably the latter.

        The predictions I’m talking about are the ones made by the climate scientists devoted to their spreadsheets, manipulating data to suit their climate belief.

        Had the bug hit, they might not have the facilities they do now, in which case, working out 100 year climate predictions with paper and pencil would not have been worth the bother.

        That’s why I say that “In some ways it’s a shame the millennium bug was fictitious.” Emphasis on ‘in some ways’

        It was supposed to be a flippant remark, not intended to be taken seriously.

        My mistake, I didn’t explain it well enough.

      • HotScot permalink
        September 7, 2017 8:50 pm


        I suspect the pharmaceutical company you worked for adopted the precautionary principle and changed its OS, just in case. Fair enough.

        The division of the pharmaceutical company I worked for at the time (Merck) didn’t bother changing much, as far as I could gather, although I only worked with their marketing databases so I defer to your experience.

      • quaesoveritas permalink
        September 7, 2017 9:53 pm

        No, the old computer system would have stopped working.
        Possibly Merck was better organised than the firm I worked for.
        The system was developed in house and was replaced by an “off the shelf” system which was probably better written.
        I don’t think we were the only firm in that position.

  4. quaesoveritas permalink
    September 7, 2017 12:36 pm

    Yesterday the BBC sowed confusion in an interview with Chis Fawkes.
    It started with Simon McCoy saying “ONE of the most powerful storms ever recorded in the North Atlantic has been battering the islands of Antigua, Barbuda and Anquila, causing major damage”, so far so good.
    Then Fawkes went on to say “it’s second strongest hurricane EVER, there’s only been one other hurricane stronger and that was back in 1980, hurricane Alan.”, when what he mean’t was “the second strongest hurricane in the modern record.”
    He did mention later that it was the second strongest on record but also mentioned the labour day hurricane and hurricanes Gilbert and Wilma, which also had 185 mph winds, which meant that Irma was only the JOINT second strongest, although he didn’t say that.
    He did suggest that “this was as strong as hurricanes can get”, but added that with “global warming”, “you might expect them to get stronger over time.”

  5. September 7, 2017 12:48 pm

    Reblogged this on Climate Collections.

  6. Gerry, England permalink
    September 7, 2017 12:50 pm

    With the sun releasing the largest flare in a decade and a CME heading our way, it will be interesting to see how this affects the path of the hurricane and the intensity. The theory is that weather events are intensified by strong solar wind.

    • HotScot permalink
      September 7, 2017 9:04 pm


      From what I read, the flare was directed away from earth. So whilst it has been detected, the MSM would have us believe it is dedicated to the destruction of the planet. Like everything else.

      I read an article by James Dellingpole in the Spectator, interviewing James Lovelock (father of the Gaia principle, now turncoat ‘denialist’) who stated that the Sun has expanded by 30% with no detrimental effect on planet earth.

      I have no idea what time period he’s talking about, but dial that in over our planets history, then compare it to a solar flare, and I suspect the effects are incomparable.

  7. RAH permalink
    September 7, 2017 10:18 pm

    Here is the PDF from NOAA explaining the methods used to determine wind speeds by the hurricane hunters. It seems that “Stepped Frequency Microwave Radiometer (SFMR)” is the key. Dropsondes can’t give them sustained wind speeds because the are descending too fast.

    Click to access PowellEstWinds_1.pdf

    I too have questions about the accuracy of their methods for determining what the 1 minute sustained wind speed of a hurricane at sea is at 10 meters above the surface when the storm is at sea because at landfall it seems the surface stations always show considerably lower wind speeds than those from the hurricane hunters.

    Fact is even wind speed measurements taken by buoys are subject to questioning because wave action can obstruct the wind flow or focus it.

  8. Dermot Flaherty permalink
    September 8, 2017 8:31 am

    Sept 8 and a good day for the Climate Changists on the “Today” programme.

    Having failed yesterday in an interview with Gaston Browne (Antigua and Barbuda PM), to get his to unequivocally blame CC for IRMA, Sara Montague had another go this morning with Baroness Scotland, the Commonwealth Secretary General.
    Two minutes or so after a discussion about what was being done to help the British Overseas territories in the Caribbean (two minutes which comprised mostly flannel responses from what seemed to be a not very well informed Sec Gen), Sara Montague hit t pay dirt with her “do you blame Climate Change?” question and the Sec Gen launched into an unequivocal endorsement of CC and its”existential threat”.

    Considering that there have been a number of reports suggesting that the UK has been less than well-prepared to help out with this disaster, it was interesting that the Sec Gen should be most vociferous on CC rather than the boring practicalities of actually helping the people in the Caribbean.
    There could have been an interesting discussion on the resources needed (RN ?) and the role Govt. agencies should play (MOD, Overseas Aid ?) but no. The Today agenda was clear. Find someone who will blame CC.
    Of course Baroness Scotland is not without form here being a well-known CCist and a less than universally admired Sec Gen.
    Even the BBC has been forced to admit she is not without her critics.
    See this story –

    About 40 mins later, the programme lost all touch with reality with an interview with Prof Myles Allen and Tom Burke re the feasibility of getting compensation for CC-caused damage from businesses that contribute to CC.

    • quaesoveritas permalink
      September 8, 2017 9:09 am

      It annoys me that the BBC allows largely unqualified people like Baroness Scotland to make statements attributing bad weather to “climate change”, totally without challenge.
      Unfortunately present circumstances offer a golden opportunity for advocates of “climate change” to make their case, in the absence of any real facts.
      The BBC seem to be “fishing” for such comments at every opportunity to support their “climate change” agenda.

  9. Dermot Flaherty permalink
    September 8, 2017 9:52 am

    As far as I know, there is agreement (and there has been for a number of years) that there is some correlation between the ENSO cycle and tropical cyclone activity. A paper I have found here –

    Click to access 2004_ENSOWarming_GRL.pdf

    is certainly beyond my meteorological knowledge but it strongly suggests that there is such a correlation and it also seems to suggest (although I freely admit that I might be misundersrtanding the detailed science) that there is a delay between the establishment of surface temperature equilibrium and effects on the hurricane season.

    I further understand that it is La Nina (rather than El Nino) that has the greater effect on Atlantic hurricanes and since I think the last La Nina was in 2016, could this be having an effect today ?

    I am anxious NOT to make the same mistake as the Climate Change crew and leap to a single simplistic answer but I have not see any mention of ENSO with regard to the current crop of hurricanes and I wonder if anyone can suggest why not ?

    Is it clear that ENSO has nothing to do with it ?
    Or is the above statement too simplistic to make in regard to the most complex system (the climate) we have on earth ?

Comments are closed.

%d bloggers like this: