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Super Typhoon Yolanda

November 9, 2013

By Paul Homewood


Sadly it appears that at least 1000 lives have been lost in Typhoon Yolanda (or Haiyan), that has just hit the Philippines. There appear to have been many unsubstantiated claims about its size, though these now appear to start being replaced by accurate information.

Nevertheless the BBC are still reporting today

Typhoon Haiyan – one of the most powerful storms on record to make landfall …….The storm made landfall shortly before dawn on Friday, bringing gusts that reached 379km/h (235 mph).


Unfortunately we cannot always trust the BBC to give the facts these days, so let’s see what the Philippine Met Agency, PAGASA, have to say.







So at landfall the sustained wind was 235 kmh or 147 mph, with gusts upto 275 kmh or 171 mph. This is 60 mph less than the BBC have quoted.

The maximum strength reached by the typhoon appears to have been around landfall, as the reported windspeeds three hours earlier were 225 kmh.

Terrible though this storm was, it only ranks as a Category 4 storm, and it is clear nonsense to suggest that it is “one of the most powerful storms on record to make landfall




Given the geography of the Pacific, most typhoons stay out at sea, or only hit land once they have weakened. But in total terms, the busiest typhoon season in recent decades was 1964, whilst the following year logged the highest number of super typhoons (which equate to Cat 3 +). Of the eleven super typhoons that year, eight were Category 5’s.





So far this year, before Yolanda there have been just three Category 5’s, none of which hit land at that strength.


Personally I don’t like to comment on events such as these until long after the dust has settled. Unfortunately though, somebody has to set the record if we cannot rely on the BBC and others to get the basic facts right.



In case anyone thinks I am overreacting, take a look at the Daily Mail headlines.




Just looking at it again, is it possible the MSM are confusing mph with kmh? It seems a coincidence that PAGASA report 235 kmh.



I have just registered a complaint at the Press Complaints Commission against the Mail article. If anyone spots similar articles elsewhere, and I will add them to my complaint.



I seem to have been right about the kmh/mph confusion!

I’ve just scanned down the Mail article and seen this:




Unless they think “gusts” are less than “winds”, it looks like someone has boobed.

  1. November 9, 2013 7:16 pm

    Reblogged this on Real Science.

  2. Andy permalink
    November 9, 2013 7:42 pm

    How do you mean “someone has to set the record straight”. Show us an actual weather station data trace showing it was only Cat 4 and not Cat 5 at landfall. All you are doing is comparing one estimate to another. How do you know the Philippine Met Agency guide is not too low rather than too high like the Joint Typhoon Warning Center estimate of Cat 5?

    You’re not setting the record straight at all I’m afraid. You will not get that until you have data points.

    Feel free to keep bashing the BBC rather than putting up some scientific measurements though if it makes you feel better.


    • November 9, 2013 8:21 pm

      I am sure the BBC know much more than the experts on the ground do.

      BTW The Philippine’s forecast three hours before landfall stated

      225 kph

      Check out 5A

      Or check out this New York Times report.

      Before the typhoon made landfall, some international forecasters were estimating wind speeds at 195 m.p.h., which would have meant the storm would hit with winds among the strongest recorded. But local forecasters later disputed those estimates. “Some of the reports of wind speeds were exaggerated,” Mr. Paciente said.

      The Philippine weather agency measured winds on the eastern edge of the country at about 150 m.p.h., he said, with some tracking stations recording speeds as low as 100 m.p.h.

      It is a pity the BBC don’t bother to check facts before they print their rubbish.

    • Streetcred permalink
      November 9, 2013 11:52 pm

      Bummer, Andy … you bin’ pwnd !

  3. LexingtonGreen permalink
    November 9, 2013 7:58 pm

    Would this one qualify for a press complaint or is it universally accepted that if it is weather related, the Guardian is not accurate.

  4. November 9, 2013 8:09 pm

    I’ve complained to the Beeb, FWIW .

  5. November 9, 2013 8:11 pm

    Article here, by the way

  6. Scott Scarborough permalink
    November 9, 2013 9:47 pm


    In the Wikipedia table for the year 1965, how can there be 10 Typhoons but 11 Super Typhoons? How can there be one Super Typhoon that does not qualify as a Typhoon?

    • November 9, 2013 10:40 pm

      Typhoons are the ones that are not “super”. So it’s “typhoons” + “super typhoons” for the total number.

      Don’t worry, it had me going as well until I added them up individually!

  7. roger permalink
    November 9, 2013 9:49 pm

    You have to marvel at the extent of the woeful basic ignorance of 21C reporters.
    That would be forgivable if lessons were learned and the ignorance not repeated.

  8. November 9, 2013 11:12 pm

    Journalism schools require no math classes. That is why it is such a popular field of study at university.

  9. gregole permalink
    November 10, 2013 12:57 am


    Thanks for the numbers and the post – good work. A whopper of a storm; but nothing like the ministers of propaganda would have us believe.

    One really has to wonder just what is the point of all these misstatements; after all they are just statements of physical fact; wind-speeds at a point in space in time. Why lie?

    Exaggeration at work to sensationalize the event one can suppose. Just like the exaggeration of so-called Man-Made global warming; if any it is minute; and affecting weather; minute if at all.

    As the saying goes, nothing ruins truth like stretching it!

    What ever happened to real journalism. Truth is actually quite interesting. All these fabulations are actually just tiresome.

  10. Gamecock permalink
    November 10, 2013 1:02 am

    There has never been a tragedy so severe that the Left wouldn’t exploit it.

    This storm does them no good if it was just another storm. They want more death and destruction, otherwise, it’s useless.

  11. b4llzofsteel permalink
    November 10, 2013 2:55 am

    I am in Manila currently and we were lucky that the super typhoon was 400 km away. Except for heavy rain nothing of the worse things happen here.

    More than 10.000 dead people already been accounted for, amongst some of my wife’s family and here people quarrel about whether BBC was right or wrong. I’don’t give a flying f*ck if it is 275 or 375 km, people die here or their houses and businesses are being destroyed, for christ sake some dignity is in place here.

    I’ve seen TV life reports her and I tell you i have never seen anything in my life…

  12. November 10, 2013 2:40 pm

    SSHS uses 1-minute sustained wind data. It is clearly a Cat. 5 storm. That 230 kph reading was a 10-minute one.

    It is clearly a clear candidate as the strongest landfalling storm. The other three were Camille(305 kph winds were recorded by recon. aircraft prior to landfall), Labor day hurricane(lowest barometric pressure of 892 mbar measured at land) and STY Megi(lowest barometric pressure estimate at the time of landfall, 885 mbar).

  13. November 11, 2013 10:08 am

    The evidence was on the method.

    JMA and PAGASA uses 10-minute sustained wind measurement. While, JTWC and NOAA used 1-minute sustained wind measurement.

    By writing this article, you have clearly shown that you have no background in meteorology whatsoever.

    • November 11, 2013 12:01 pm

      Hi. Is it right to name Yolanda as a hurricane??? I’m currently arguing with one my colleagues; he used the term hurricane on his status post in fb. I said that it is categorized as super typhoon and not as hurricane. Please enlighten me. Thank you.

      • November 11, 2013 1:41 pm

        Typhoons and hurricanes are the same – just different names.

        In the Atlantic and Eastern Pacific, they are called hurricanes. And in the Western Pacific they are typhoons.

        They are also called cyclones in the Indian Ocean and South Pacific.

    • November 11, 2013 1:38 pm

      You miss my point.

      What evidence do you have that the 1-minute readings would make it the strongest? I appreciate that the 1- minute speeds would likely be higher, but by how much?

      • November 11, 2013 2:46 pm

        Hurricane Camille windspeed reading prior to landfall was a 1-minute sustained wind reading. It makes sense to compare.

        In the 10-minute scale, it is a place below Typhoon Megi in terms of being the strongest landfalling hurricane.

        Here are the rankings:

        1-minute sustained winds:
        1. Nancy
        2. Violet
        3. Ida
        4. Haiyan

        10-minute sustained winds:
        1. Tip
        2-4. Megi, Bess, Haiyan

        Barometric pressure(10-min)-JMA:
        1. Tip
        2-3. Nora, June

        Barometric pressure(1-min)-JTWC:
        1. Tip
        2-5. Gay, Ivan, Joan, Keith, Zeb

        I still believe that Megi is the strongest storm to hit land. But you can’t just set aside the difference between 10-min and 1-min measurements, and ridicule the 1-min ones.

      • November 11, 2013 5:30 pm

        It’s interesting that PAGASA only recorded gusts up to 171 mph.

        John Fuller refers to Chris Landsea’s rule of thumb that 1-min adds 12% to the 10-min speeds, which would take the 147mph up to 165 mph.Very rough and ready I know.

        But 165 mph is also what you get when you take 15% off the 195 mph for land friction.

        All grist to the mill!!

        (BTW – thanks for the advice – much appreciated)

    • November 11, 2013 3:22 pm

      I did some sleuthing of my own and from what I can tell, agar012 is correct. It’s good that you are questioning the media, but I believe your information is also lacking. Of course, my information is also lacking as I had limited time to look this stuff up. Google search is all you need though. 😉

      Some media reports actually do get into the differences that you have pointed out.

      This article mentions numbers from several sources and goes on to explain.

      > In a study, the Manila Observatory explained the difference in the predictions: JTWC records wind speeds at 1-minute average while PAGASA reports it at 10-minute average.

      As you might imagine, a 10 minute average is going to give you different numbers than a 1 minute average. It seems that the 10 minute average generally gives you lower numbers.

      > One complication with the use of the 1 min averaging time for the standard for sustained wind in the Atlantic and Northeast Pacific tropical cyclone basins (where the United States has the official World Meteorological Organization tropical cyclone advisory responsibilities) is that in most of the rest of the world, a 10 min averaging time is utilized for “sustained wind”. While one can utilize a simple ratio to convert from peak 10 min wind to peak 1 min wind (roughly 12% higher for the latter), such systematic differences to make interbasin comparison of tropical cyclones around the world problematic.

      From that info, if you add 12% to 235 then you get 263.2 which is a cat 5 hurricane.

      Those numbers are still below the highest numbers coming out of JWTC, but as you pointed out, the highest numbers come in while the hurricane is over water. Here is another article which has another spin.

      > Typhoon and hurricane maximum wind speed estimates are only valid for over water exposure, and winds over land are typically reduced by about 15%, due to friction. This would put Haiyan’s winds at 165 mph over land areas on the south shore of Guiuan Island. This is equivalent to a high end EF-3 or low end EF-4 tornado, so the wind damage there must have been catastrophic–perhaps the greatest wind damage any place on Earth has endured from a tropical cyclone in the past century

      Winds at 165mph converts to 265.542kmh, so those number jive with the 10 minute to 1 minute conversion. It also supports what you mentioned in another comment, which is that placing 195mph winds at landfall would have been an exaggeration. But this is still a cat 5 hurricane.

      This article goes to to explain.

      > *I just want to note that the maximum wind speeds and minimum pressures are just estimates from satellite data and not actual measurements from stations. These values are typically obtained by “hurricane hunters”, aircraft that are designed to fly into hurricanes are take these specific measurements. Unfortunately, or perhaps more fortunately, for whatever reason no hurricane hunters sampled Super Typhoon Haiyan. But these estimates, while not absolute are still pretty robust.

      So, these numbers are estimates from satellite data, but most of the info you would be comparing is probably using data collected the same way. It would be great to get true numbers, but those numbers are difficult to get in reality. The stations would have to be right at specific spots at specific times and they would have to be able to collect this data without being destroyed.

      This is quite the rabbit hole. I’m sure I could go on for hours or even years. I could probably make a career out of this stuff. 😉

      I’m posting this info more as a collaborative learning exercise rather than to prove anyone right or wrong. You started it off with valid questions and I feel this is just taking the conversation a bit further. Maybe we could take it even further, but I think the above info does a good job at showing why the reports seem so conflicting.

      • November 11, 2013 5:05 pm

        Good stuff, thanks John.

        I would add one point. Chris Landsea has stated that :

        many times during the late 1940s the aircraft often did not penetrate the center of hurricanes with central pressures in the 950s or even the 960s. If this criteria of, say, a 960-mb threshold were utilized, many of these cyclones would have been listed with a peak intensity of only Category 3 strength.”

        I can’t say as I blame them! But it obviously makes it difficult to compare hurricanes then and now.

  14. November 12, 2013 5:56 am

    A couple more good articles. The first I wish I would have found when I first started looking into this as it would have saved me some time. 😉 It covers a lot of the same things I mentioned in my last comment.

    Some interesting points…

    > The Japan Meteorological Agency (JMA), which uses their own techniques to estimate typhoon strength via satellite imagery, put Haiyan’s peak strength at 125 knots (145 mph), using a 10-minute averaging time for wind speeds.

    This is good info because the JMA numbers match up with the PAGASA numbers and it mentions that JMA uses satellite imagery. I was previously unable to find what methods these organizations used for collecting their data. I was thinking maybe they were using radar or some other method, but in fact it appears they probably use the same data as JWTC, but they have different methods for interpreting that data.

    > Winds estimated by either JMA or PAGASA for Haiyan have appeared in the media, resulting in some confusion about what the typhoon’s winds were at landfall. The averaging time used by JTWC and NHC is 1-minute, resulting in a higher wind estimate than the 10-minute average winds used by JMA and PAGASA in their advisories. To convert from 10-minute averaged winds to 1-minute average, one conversion factor that is commonly used is to multiply by 1.14–though lower conversion factors are sometimes used.

    Indeed. As you have mentioned in this article. There is all sorts of crazy information in the media.

    > JMA satellite strength estimates are consistently much lower than those from JTWC for high-end Category 5 strength typhoons, and JTWC estimates are the ones most commonly used by the hurricane research community.

    This is another interesting point. Going back to a previous quote, PAGASA and JMA appear to be using satellite imagery for their estimates. Again, they are probably using the same imagery as JWTC. Even accounting for the conversion, the JTWC numbers are much higher than what anyone else comes up with.

    The maximum wind of 125 knots is for the entire life cycle of the typhoon, not just at first landfall. That means we can disregard the 15% adjustment over land that we had discussed earlier. That the numbers matched up must be a coincidence. The U.S. just does everything weird. Maybe that’s because we feel like we can. Damn Yankees.

    This all shows that coming up with these estimates is an inexact science. And of course typhoons are highly chaotic events. Coming up with numbers for the gust speeds is probably more inexact than sustained wind speeds. I imagine a 1 minute reading would be highly variable, which may explain the higher numbers. You could probably even argue that a 1 minute reading could be a gust.

    And another good article…

    > If the higher estimates are correct, the warning center said Haiyan’s maximum strength would exceed that of its previous record-holder: Hurricane Camille, which hit the northern Gulf Coast in 1969 with sustained winds of 190 mph.

    But as we now know, making comparisons to anything from 1969 is comparing inexact to wildly inexact. At least with modern storms we have archived data that we can follow and even come up with our own methods for estimating wind speed. It would be interesting to feed that data into a program which would show how different organizations are coming up with their numbers.

    > “Was it better developed than Hurricane Wilma in 2005, or Katrina at its peak? We really can’t say, because we didn’t have any hurricane hunters flying in this to actually measure the winds,” Norcross said.

    Key words here. WE REALLY CAN’T SAY. We have this satellite data and we make estimates. Really, we could just be pulling numbers out of our asses.

    > In addition to the Hawaii-based warning center, China, Japan and Taiwan have typhoon-monitoring agencies, “but there’s no coordinated effort,” Emanuel said. He recommended setting up an international center and using typhoon-hunting airplanes — or robotic drones, for that matter — to keep track of the typhoons of the future.

    We have come a long way since the 60’s but we still have a long ways to go.

    As inexact a science as this is. This is the best we have for a shared standard for measure. Even if hurricane hunters were to come up with hard numbers, it’s probably the JWTC numbers which go into the record books.

    Another limiting factor in the numbers we are using is they don’t take into account things like rainfall. Winds create a mess, but it’s the floods which cause the massive casualty counts.

    We could also use the descriptions of the category levels as a guide.

    > Catastrophic damage will occur: A high percentage of framed homes will be destroyed, with total roof failure and wall collapse. Fallen trees and power poles will isolate residential areas. Power outages will last for weeks to possibly months. Most of the area will be uninhabitable for weeks or months.

    Looking at the images coming out of the Philippines. Cat 5, jury dismissed. 😉

  15. Danna Dada permalink
    December 15, 2013 1:13 am

    PAGASA uses 10-minute sustained winds. Saffir-Simpson Hurricane Scale uses 1-minute sustained winds which is the basis of determining the Category of a storm. 1-minute sustained wind is quite higher than 10-minute sustained wind.


  1. Super Typhoon Yolanda (Haiyan) | CACA

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