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Hurricane Dorian–The Facts v The Myth

September 6, 2019

By Paul Homewood

 

 Devastation in the Abacos, northern Bahamas

Devastation on the Abaco Islands, after Hurricane Dorian

Let me start by confirming the very real devastation left by Hurricane Dorian in the Bahamas, particularly the Abaco Islands, which took the direct hit.

According to the BBC:

The death toll from Hurricane Dorian in the Bahamas will be "staggering", the country’s government has warned as aid efforts are being stepped up.

The official death toll stands at 30, but is expected to rise further.

Officials are sending morticians and 200 body bags to the Abaco Islands, the worst-hit part of the archipelago.

 

Nevertheless, we need to analyse what actually happened.

It has been widely reported that sustained wind speeds reached 185 mph, with a peak pressure of 910 mb.

This would make Dorian the second strongest Atlantic hurricane:

image

https://en.wikipedia.org/wiki/List_of_Atlantic_hurricane_records#By_pressure

 

But are we comparing like with like? I have even seen the BBC claim that Dorian was as strong as the Labor Day hurricane of 1935. But this is simply absurd.

There were no satellites or hurricane hunter aircraft around in 1935 to measure wind speeds. All hurricanes lose intensity when making landfall, so the numbers for the Labor Day storm, which were based on landfall, cannot be compared to Dorian’s, taken out in the Atlantic. (Peak intensity for Dorian occurred just before its eye hit the Abacos, which, being small and low lying, would have had little impact on its intensity.)

As with most hurricanes of that era, the wind speeds in 1935 were not directly measured. In the Labor Day’s case, it was estimated from the barometric pressure, which was recorded on land at the centre of the hurricane as 892 mb. The instrument was subsequently carefully checked by the Weather Bureau in Washington, and found to be accurate. Theoretically, such a pressure should indicate windspeeds of 186 to 189 mph, but this was adjusted down to 185 mph at the time. Almost certainly though, winds before landfall would have been higher, probably around 190 mph.

Clearly, in theory, Dorian should have been nowhere near as powerful as the Labor Day, with a much higher pressure of 910 mb.

Indeed, when we look at the most intense Atlantic hurricanes by pressure, we see a much different picture than the one portrayed by the supposed wind speeds:

image

https://en.wikipedia.org/wiki/List_of_Atlantic_hurricane_records#By_pressure

 

At 910 mb, Dorian had the same pressure as the Cuba hurricane of 1924, which only had windspeeds of 165 mph. The comparison is a telling one.

As with Labor Day, Cuba’s windspeeds were estimated from nearby barometer readings, both at sea and on land. It is, of course, rare that there would be any such readings at the centre of powerful hurricanes, not least because ships would try to avoid them.

If the same methodology of using barometric pressure had been used for Dorian, the winds would have been estimated at 165 mph.

The other “Cuba” hurricane on the list, in 1932, also makes a pointed comparison. The hurricane had been tracked (involuntarily, as its funnel had been blown off!) by a ship, the SS Phemius. Shipboard instruments recorded a minimum pressure of 915 mb, now accepted as the official figure. However, as the ship was not within the hurricane’s eye, the true pressure must have been less. The record says Cuba was not as strong as Dorian, but how do we know?

Inevitably, there must have been many more hurricanes in that earlier era, where there was no pressure data available to record the peak intensity of the storm.

 

Clearly the numbers being spewed out these days from satellite data can in no way be compatible with measurements form earlier hurricanes.

Which brings us back to Dorian.

As I have pointed out many times before, the “actual windspeeds” are nothing of the sort. They are only what the “forecast track” predicted.

In Dorian’s case, the actual data from satellites suggested speeds of around 120 kts, or 138 mph.

2019AL05_AMSUTSPL_201909051200

http://rammb.cira.colostate.edu/products/tc_realtime/storm.asp?storm_identifier=AL052019

 

Digital Dvorak estimates also imply speeds of not much more then 120 kts:

2019AL05_DGTLDVOR_201909041500

http://rammb.cira.colostate.edu/products/tc_realtime/storm.asp?storm_identifier=AL052019 

 

 

According to the National Hurricane Centre, the warning intensity was based on data from a reconnaissance plane:

image

https://www.nhc.noaa.gov/archive/2019/al05/al052019.discus.034.shtml?

 

This aircraft data was actually provided by Stepped Frequency Microwave Radiometers (SFMR), but these have only been in operational use since 1984. Whether this system is more reliable in estimating surface wind speeds than other methods is immaterial, as you are comparing apples and oranges.

Using it to compare with hurricanes prior to 1984 is grossly misleading.

In any event, there are acknowledged problems with the system, particularly shoaling, as the National Hurricane Center admit:

image

 https://r.search.yahoo.com/_ylt=AwrJQ5vgZXJdWQsAaHVLBQx.;_ylu=X3oDMTBydWZibG83BGNvbG8DaXIyBHBvcwM4BHZ0aWQDBHNlYwNzcg–/RV=2/RE=1567807072/RO=10/RU=https%3a%2f%2fwww.nhc.noaa.gov%2foutreach%2fpresentations%2fnhc2013_aircraftData.pdf/RK=2/RS=sbCHHAqqEGsPkCUDwXYD6uvcMHE-

 

All of the evidence suggests that Dorian was no more than a 165 mph storm, and maybe less, still of course Cat 5 and extremely damaging. But nonetheless an altogether too common event in that part of the world.

Indeed, the damage on the ground, much of which was presumably due to storm surge, catastrophic as it is, could have nevertheless been consistent with a Cat 4 storm.

There is no evidence whatsoever that Dorian was the second most powerful Atlantic hurricane on record.

45 Comments
  1. jack broughton permalink
    September 6, 2019 3:24 pm

    Superb, objective analysis, Paul.
    How do you manage these detailed articles and cycling?

  2. The Old Bloke permalink
    September 6, 2019 3:38 pm

    I have been tracking this storm since Sept 1st when all the talk was off a record breaking storm. There is a plethora of weather recording stations along the eastern side of the USA coast and quite a few within the Bahamas islands.I have been keeping people posted on my Facebook page of the winds at ground level as they happen night and day. Of all the stations that took a hit from Dorian, the highest wind speed I saw recorded (and that was a gust) was 106 km/h. Not miles per hour or knots but Km/h. I even tracked the NOAA aircraft one evening on the Flightradar web site. Nowhere on mainland USA have I seen any wind speed over 85 km/h from personal or commercial reporting stations. It might well be that the wind speed within the so called “Hurricane” cell was at Hurricane force but probably at 20,000 ft.
    If in fact a wind speed of 163 mph was recorded, then it must have been a very small thumb print of an area and one has to ask, just where was it?

    • JimW permalink
      September 6, 2019 3:51 pm

      I agree. Since Irma and being personally involved I have taken a keen interest in these hurricanes. It seems to me that what NHC/NOAA issue as windspeeds at 10m is really at several thousand metres up. No ground based station records the same speeds.
      The two islands have suffered severe surge damage but structures away from the shore look like they have mainly survived the wind. It looks like Cat2/3 damage to me. Bad enough without the exageration of NHC.

    • JKintheUSA permalink
      September 7, 2019 4:24 am

      Hi! I thought NHC wind speeds were a bit exaggerated too. However dropsonde data seems to back up reported Hurricane Dorians wind speeds pretty closely. There still may be 10% or so added to the dropsonde measured wind speeds IMO. For a ground measurement of approximately 142 Km/h, see NOAA Buoy Station SPGF1, actually a ground station in NW Bahamas, which reported gusts at 39.6 m/s on 9/3 at 0500GMT. I believe this ground station was a bit south of the eye wall, so it probably did not experience maximum wind speeds. URL for data for this ground station is https://www.ndbc.noaa.gov/data/realtime2/SPGF1.cwind.

  3. September 6, 2019 3:49 pm

    And the news media cannot simply report the facts but always used exaggerated adjectives to cause fear mongering and increase ratings. I wish we really had true journalists and not these political hacks in news media.

    • Gamecock permalink
      September 7, 2019 12:12 am

      Dude, you have true journalists.

  4. The Old Bloke permalink
    September 6, 2019 3:49 pm

    As an addition to my previous post, I am still being told that Dorian is a Cat 3 Hurricane, yet directly underneath said Hurricane is this recording station. As you can see from the link, the winds are no where near the 119-153 km/h needed for the storm to be a Cat 1 Hurricane:
    https://www.wunderground.com/dashboard/pws/KNCKNOTT6

  5. rah permalink
    September 6, 2019 5:09 pm

    I doubt it was even a CAT V.
    The eye sat either over land or shallow water for 40 hours in the Bahamas. Even the feeder bands out over deeper waters used up the thermal energy available from the warmer surface waters. The convection engine of a hurricane requires thermal energy and Dorian starved from lacking it and thus what was declared to be a CAT V degraded to a CAT II. Also the storm went through an eye wall replacement cycle in which the eye of the storm essentially doubled in size and laying over the islands it never could tighten up and regain the organization it had prior to that. As the storm got weaker the wind field expanded as typically happens. Though a storm that has gone through such a transition can regain some strength it is very difficult for one to return to the tight, well formed, compact powerful convective engine it was before even under ideal conditions and a hurricane running along or near or with part of it over the coast is certainly not ideal for strengthening. Coastal waters are generally shallow waters so the thermal energy of the warm surface water is used up quickly and there is no place for the storm to draw more in from on that side of the storm.

    No surface stations or buoys reported anything like the 185 mph sustained and gusts over 200 mph winds you were hearing on TV. But apparently this time, unlike during several previous hurricanes I have monitored, there were no operational buoy or surface stations that were right in the path of the eye wall that allows me to check on the veracity of the wind speed claims when the storm was at it’s peak of power. However based on past events when I could check such data out, I don’t believe for a minute those high wind speeds reported are accurate. The simple fact is that NOAA has established a history in the last decade of inflating the windspeeds of hurricanes and tropical storms relative to the classic Saffir Simpson criteria of the maximum wind sustained 1 minute at 10 meters above the ground by an unmasked surface station. If the winds were as strong as they claimed the places that passed under the eye wall would be wiped pretty much clean by the EF5-tornado like winds of gusts over 200 mph they were reporting. Cars, truck trailers, and shipping containers would be thrown far and wide not just washed or blown over and moved short distances as I am seeing in the video of the damage. No conventional structure can stand up to EF-5 tornado speed winds. When the EF-5 tornado hit Joplin, MO a few years ago it actually pushed the stone and brick hospital in that town off it’s foundation.

    That is not to say that Dorian was not a bad ass killer storm. It most certainly was. I would guess it was closer to a solid CAT IV than V at it’s peak. It was, based on the damage, most certainly NOT tied with the 2nd most powerful storm in the satellite era as claimed. As a practical matter of survival such a distinction doesn’t make much difference. The only safe thing to do when a storm gets that strong is get the hell out of the way. People and structures on low lying islands are completely at the mercy of the sea. Typically it’s the storm surge and flooding that causes far more damage and kills far more people than the winds and that will be the case this time.

    Give the claims that hurricanes are slowing down and have a greater tendency to stall due to climate change and thus are causing more damage no credibility. I’m not going to get into the nitty gritty details to debunk that lie though I could. I will just attack the whole premise of the claim. Why just hurricanes? Climate change is supposed to be global and if warming is causing hurricanes to slow, stall, and sometimes loop, then why aren’t all tropical cyclones everywhere doing so? If the “news” people that are nodding their heads and accepting such claims as fact weren’t ignorant, biased, nitwits, that would be the very first question the liars making that claim would have to answer and they wouldn’t have one.

    The whole foundation of science and the scientific method lies on the ability to think critically. To intelligently question not only new hypotheses, but well established theories and even what are considered established facts . To use one’s own mind and not uncritically accept dogma. This necessary characteristic is not being taught these days and it shows. A teacher, a real teacher, will do their best to instill that skepticism, to get their students to question and reason for themselves and that is one of greatest skills that one can instill in a young mind.

  6. Joe Public permalink
    September 6, 2019 5:14 pm

    1780 was a disastrous year for hurricanes.

    “The Great Hurricane of 1780, also known as Huracán San Calixto, the Great Hurricane of the Antilles, and the 1780 Disaster, is the deadliest Atlantic hurricane on record. Between 22,000 and 27,501 people died throughout the Lesser Antilles when the storm passed through them from October 10–16. Specifics on the hurricane’s track and strength are unknown because the official Atlantic hurricane database goes back only to 1851.”

    https://en.wikipedia.org/wiki/Great_Hurricane_of_1780

    “The 1780 Atlantic hurricane season ran through the summer and fall in 1780. The 1780 season was extraordinarily destructive, and was the deadliest Atlantic hurricane season in recorded history with over 28,000 deaths. Four different hurricanes, one in June and three in October, caused at least 1,000 deaths each; this event has never been repeated and only in the 1893 and 2005 seasons were there two such hurricanes.”

    https://en.wikipedia.org/wiki/1780_Atlantic_hurricane_season

  7. Michael Adams permalink
    September 6, 2019 6:37 pm

    I can add nothing to the debate but I do wonder if this is a turning point in western civilisation. There are certain points in history when seemingly small changes have led to significant shifts in power and maybe we are witnessing one of them. I’m referring to the Climate Change debate, or rather, the lack of publicised debate.

    What we are seeing is a change in scientific rigour through lack of challenge and scientific skepticism. One side of the argument has been generally accepted by the media, governments etc. and the other side, consisting of data interpretation, challenge etc. is being blocked out. This is now deemed acceptable and can only lead to a lack of scientific challenge which has dominated science in the West, and the East as far as I know, for a large proportion of the time that we have grown in knowledge and confidence. If this continues and spreads to other areas of science surely this would weaken our society and lead to it decline. Could this be a turning point?

    • A C Osborn permalink
      September 6, 2019 7:52 pm

      Your question is interesting, but the “turning point” may not be what you think.
      If the other Scientists are correct and the Earth continues to cool form the 2016 El Nino the current crop of Climate Scientists are going to be totally ridiculed over their current claims.
      It could actually bring the whole of Climate Science in to disrepute.
      Medicine is already heading in that direction.

      • C Lynch permalink
        September 6, 2019 10:44 pm

        They’ll just pretend the planet cooling was caused by global warming and pretend they predicted it. Most of the public have the memory and attention span of a goldfish nowadays which enables this type of deceit. This fraud is backed by just about all the choke points of piwer: the Media, government, education, academia etc. The will fight long and dirty before they admit defeat.

      • Gerry, England permalink
        September 7, 2019 5:40 pm

        It does help that NASA are saying that the next solar cycle will be the lowest in 200 years but without acknowledging any of the things that happened to the climate at that time.

  8. September 6, 2019 6:57 pm

    Paul. Here’s another effort to blame ‘global heating.’ Stefan Rahmstorf (Potsdam Institute for Climate Impact Research) tweets – https://twitter.com/rahmstorf/status/1169027771605164033:

    The @WMO TC expert team finds in its 2019 report that “ten of 11 authors concluded that the balance of evidence suggests that there is a detectable increase in the global average intensity of the strongest (hurricane-strength) TCs since the early 1980s”. https://journals.ametsoc.org/doi/pdf/10.1175/BAMS-D-18-0189.1

    “. . since the early 1980’s. Talk about cherry picking. Thinking back to your AMO graphic yesterday. Bet we’d see similar between 1910-1945. Also Interesting is both 1910 and 1980 (roughly) mark the beginning point of two global warming cycles.

  9. September 6, 2019 7:39 pm

    Good God

    “a draft UN report obtained by AFP.

    Destructive changes already set in motion could see a steady decline in fish stocks, a hundred-fold or more increase in the damages caused by superstorms, and hundreds of millions of people displaced by rising seas, according to the Intergovernmental Panel on Climate Change (IPCC) “special report” on oceans and Earth’s frozen zones, known as the cryosphere.”

    https://phys.org/news/2019-08-oceans-friend-foe-landmark-climate.html

    • September 6, 2019 9:50 pm

      Usual brainless fearmongering.

    • I_am_not_a_robot permalink
      September 6, 2019 11:09 pm

      If the IPCC bureaucrats, their thousands of hangers-on and media claque genuinely believed any of that they wouldn’t be flying from around the world in late September for their 51st beano and booze-up in that ‘budget’ holiday location viz. Monaco.
      “… Please note that due to the high number of requests, approval of registration might take a number of days …”:
      https://www.ipcc.ch/2019/08/14/media-registration-srocc-p51/

      • Adam Gallon permalink
        September 7, 2019 10:12 am

        It’s a hard life.

  10. The Old Bloke permalink
    September 6, 2019 8:53 pm

    One thing about Dorian that really made me chuckle, was when I saw a media report of the damage done to an Island in the Bahamas. The reporter stated that the storm was over the said island and was a Cat 4 storm, one of the highest ever reported for the area and as we know, it was for a few days a stalled storm. A Cat 4 storm is wind speeds of 209-251 km/h. The report was being shown from a helicopter flying low over the devastated island.
    I came to conclusion that the filming from the helicopter was not from the devastated island but from somewhere else. Helicopters do not fly above 50 knots (93 km/h) let alone 209 km/h. Our own Merlin helicopter is restricted to 50 knots. A Cat 4 Storm? Really?

    • Gamecock permalink
      September 7, 2019 12:17 am

      You are off base. Depends on the chopper. 150 mph is not an unusual top speed for civilian helicopters.

      • JKintheUSA permalink
        September 7, 2019 4:38 am

        I believe The Old Bloke was stating helicopters do fly in conditions in which the wind speeds are >= 50 knots and was not referring to the top speed of the helicopters.

      • Paul permalink
        September 7, 2019 10:55 pm

        reread the old blokes last paragraph again. He wasn’t talking about top speed

    • Adam Gallon permalink
      September 7, 2019 10:20 am

      Bell 206 Jet ranger, top speed, 240kph/150mph. Aerospatiale as350 Squirrel, Never exceed speed: 287 km/h (155 knots, 178 mph). Merlin, Never exceed speed: 309 km/h (192 mph, 167 kn). So, the Merlin can exceed your 209kph, by a mere 100kph.

  11. swan101 permalink
    September 6, 2019 9:57 pm

    Reblogged this on ECO-ENERGY DATABASE.

  12. September 7, 2019 12:21 am

    Reblogged this on Climate- Science.press.

  13. Nordisch geo-climber permalink
    September 7, 2019 8:48 am

    Hurricanes and tornadoes often create tragedy and piles of matchwood from shattered timber houses. I still don’t understand why buildings in vulnerable areas are not wind-proof and made of concrete with storm shelters. In Oklahoma, Arkansas and Texas, tornado alley demands a tornado shelter in every house. The weather is entirely predictable from satellite and radar, timings are very accurate. In theory no one should die. Hurricanes are always going to be part of life so why is there no adaptation and why repeated tragedy? Very upsetting.

    • A C Osborn permalink
      September 7, 2019 9:47 am

      Storm Shelters on these island would have to be the reverse of those in Tornado alley as they are prone to flooding by Storm Surge.
      So they would have to be built Up and not down, they would therefore have to be vey large and very substantial concrete buildigns design to allow Aiflow ove rthem like a dome for instance.

  14. john cooknell permalink
    September 7, 2019 8:52 am

    Hurricane Dorian has caused extensive damage in the Abaco islands and Grand Bahama.

    Having been there over 20 years ago, my understanding was these very low lying islands (40ft altitude max) are sparsely populated because there is nowhere safe to shelter when the hurricane comes. Unfortunately this appears to be true.

    Most of the Bahamas people live in Nassau 150 miles to the South on New Providence island which is not damaged and is safe.

    My observation was the Bahamian government encouraged development on Grand Bahama, but discouraged development on Abaco islands as the islands could not be made safe in hurricane conditions, and travel there was problematic. But as real estate was cheap people set up their homes there, and most of the time the living environment is like paradise.

  15. Harry Passfield permalink
    September 7, 2019 9:41 am

    It’s an interesting thought – well, I thought so – that if a country (like Japan) was building anything in an earthquake zone it would entail following very strict building codes for safety and resilience. However, it seems that non-first-world countries don’t have to follow such codes when it comes to living in one of the world’s foremost hurricane zones. Consequently, the destruction of what are more or less shanty towns is – and looks – all the worse and the casualties more numerous as a consequence. One can only wonder why world organisations, such as the UN, who are so keen to save the world from the slow-motion destruction of CC (hah!), are not bothered to help places like the Caribbean protect their environments from the more immediate threat of hurricanes.

  16. john cooknell permalink
    September 7, 2019 11:00 am

    As always there is a political dimension to the disaster.

    On independence from the UK in 1973 the Abaco islanders never saw themselves as part of the Bahamas (it is a long way to the capital Nassau), they wanted self rule as a separate British colony. They received a sharp “no way” from the British Parliament, UN etc.

    Ever since they have sought some sort of independence from the Bahamian government, so I would imagine there has been little central governmental focus on any development proposals, leaving it to the Abaco island council to determine such things, and they have no resources, and no help from anybody, just a few UK charities..

    Grand Bahama is different, development and investment have been encouraged by the central government.

  17. MrGrimNasty permalink
    September 7, 2019 11:26 am

    Tons of rubbish washed into the ocean to be used as an excuse for clamping down on us with more ‘plastic straw bans’ no doubt.

    Also notice the piles of destroyed cars in the news shots, many luxury, and await the insurance losses being used to prove weather is getting worse.

    Tony Heller, has dug out various old forgotten accounts of particular islands and groups getting completely swept clean by hurricanes.

    It is of course dishonest to suggest it is possible to compare storms within even recent history, let alone 100 years ago.

    And even if ‘only’ 50 have tragically died, this will be recorded as thousands officially after the alarmists have added in all the bogus associated/excess deaths – as has been usual after recent storms.

    • Hemant Beniwal permalink
      September 10, 2019 8:12 pm

      What happened in the aftermath of Hurricane Maria or other recent hurricanes is completely different than what’s unfolding in Bahamas right now. Even though climate change gang members have a reputation for inflating wind speeds, the storm surge heights can easily be verified and given that the storm surge was > 20 feet, direct fatalities will be in hundreds, if not thousands.

      • September 10, 2019 10:35 pm

        Quite right. The real threat in these hurricanes is storm surge.

  18. rah permalink
    September 7, 2019 12:06 pm

    Storm surge and not the winds directly is almost always what causes the preponderance of death and destruction in a tropical cyclone. A dome of water builds under the very low atmospheric pressures. In a powerful storm like Dorian that dome can be several meters high and 50 to 100 miles in diameter. On top of that dome are huge wind driven waves. Rogue waves approaching 100 ft. high have been recorded. Usually it is the NW quadrant where the worst storm surge is experienced.

  19. Broadlands permalink
    September 7, 2019 1:24 pm

    Stronger hurricanes are supposedly due to “global warming”. Are there any data on Atlantic sea surface temperatures to support that allegation?

    • JKintheUSA permalink
      September 7, 2019 5:20 pm

      See current post Florida Major Hurricane Strikes: No Significant Increase in Intensity from Sea Surface Warming at http://www.drroyspencer.com/

    • rah permalink
      September 7, 2019 6:52 pm

      The problem is hurricanes are not much stronger according the ACE index. And with the obvious inflation of the windspeeds being recorded I seriously doubt they are stronger at all.

      When dealing with such claims it is best to not accept the premise of the claim without checking it out first.

  20. Athelstan. permalink
    September 7, 2019 2:46 pm

    This was a terrible event, nature, sea and wind together sometimes is a violent irrepressible force and very terrible mistress at times, very sadly the Abaco Islands took the brunt of this Hurricane, too people lost all their worldly possessions and some paid the ultimate price. All human beings should bow their heads and in solemn respect.

    Britons do hope that, help reaches these people and with most urgent attendance.

    Furthermore, this is where a big and powerful navy can do so much ‘heavy lifting’ the USN is shipping out and will assist, and the RN is already there, we remark that, UK foreign aid would be far better spent on ships and complement rather than dribbling it away on tryrants, promoting NGOs the UN and eu and all of its half baked scheming in bureaucratic useless wastefulness.

    To the Bahamian islanders, we wish them all, rescuers and rescued in great and earnest entreaty – good weather, engaged assistance to efficient facilitation in the relief effort.

  21. A C Osborn permalink
    September 7, 2019 3:18 pm

    Paul, there is a very interesting article on No Tricks Zone that shows correlation between Solar Storm activity and the development of Dorian and Irma.

  22. September 7, 2019 6:01 pm

    Reblogged this on WeatherAction News and commented:
    Sadly all too often we compare modern measurements with old ones when they are not compatible. As with temperatures they may give us the sign, but not necessarily the magnitude.

  23. It doesn't add up... permalink
    September 8, 2019 10:39 am

    Looking at other hurricanes that hit the Bahamas I came across

    https://en.m.wikipedia.org/wiki/1932_Bahamas_hurricane

    Which is one of several in the 20s and 30s. It bears a striking resemblance to Dorian both in track and intensity.

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