Dr. Philip Klotzbach writes via email:
Discussion of near impossibility of actually recording strongest winds in a hurricane
Brian McNoldy and I wrote a blog for Capital Weather Gang yesterday where we called out Matt Drudge about his claims that the National Hurricane Center was over-estimating the winds in Hurricane Matthew. As you know, it is nearly impossible to measure the strongest winds in a hurricane due to a variety of factors. Brian and I covered these in some detail in this blog.
Matt Drudge commented on our story last night, and since then, there have been hundreds of comments from individuals claiming that NHC is just a cog in the “global warming” machine. As you know, I’m certainly not a fan of over-hyping climate change and have published several papers showing no trends in intense hurricane activity over the modern observational period.
I feel that it would be incredibly useful for a well-respected climate skeptic website to pick up this story and give some additional credence to it. If the eyewall of Hurricane Matthew had been 50 miles further west, it would have been devastating for the east coast of Florida! We may not be so lucky next time, and I don’t want people to become armchair meteorologists and think the winds are much less than NHC reports.
Happy to help – Anthony
Hurricane intensity is not exaggerated to scare people, and here’s how we know
By Phil Klotzbach and Brian McNoldy
Hurricane Matthew brushed the East Coast as a Category 4 in early October. It scoured the Florida coast with a storm surge that washed out roads and flooded homes and businesses. It dumped over a foot of rain on the Carolinas and triggered deadly flooding. And before all of this, Matthew devastated Haiti and killed at least 600 people — it’s possible we’ll never knowthe final death toll.
But the hurricane’s deadly encounter with Haiti and multibillion-dollar brush with the East Coast wasn’t bad enough for some people — mainly, Matt Drudge, a political commentator and news aggregator, who tweeted skepticism about Matthew’s actual intensity as it barreled toward Florida. Perhaps, he suggested, the National Hurricane Center was overhyping the storm’s maximum winds.
Drudge deletes his tweets regularly, so here’s a screenshot from the morning of Oct. 7:
“The deplorables are starting to wonder if govt has been lying to them about Hurricane Matthew intensity to make exaggerated point on climate,” Drudge mused. (“The deplorables” refers to supporters of Republican presidential nominee Donald Trump.)
Then this (image saved by the BBC):
Drudge argued the point based on data from Caribbean weather stations and buoys that were not reporting winds as strong as what the National Hurricane Center used in its advisories. But the National Hurricane Center uses a lot of different methods to determine a hurricane’s actual peak intensity, and there are some serious issues with relying simply on weather stations and buoys.
The National Hurricane Center — or NHC — uses a variety of satellite-based tools to estimate a hurricane’s winds when the storm is far from land, and as the storm moves closer to land, additional devices are employed.
Hurricane Hunter aircraft are dispatched to investigate the storm in more detail. These planes measure winds both at flight-level, which is approximately 10,000 feet, as well as at the surface through the use of a device called a stepped-frequency microwave radiometer which measures radiation transmitted from the ocean surface back up to the airplane. When high winds churn up the ocean surface, the amount of microwave radiation measured is diffused compared with the amount of radiation measured when the ocean surface is calm.
NHC also utilizes devices called “dropwindsondes” that are dropped from the aircraft at about 10,000 feet and measure temperature, humidity, pressure and wind speed as they descend to the surface. When a storm nears shore, radars can also be utilized to estimate wind velocity.
All of these different measurement devices, combined with surface observations from ships and buoys, are combined to assess a storm’s intensity.
There are several reasons buoys are likely to underestimate a hurricane’s wind.
First, buoys utilize an eight-minute average maximum wind, and NHC uses one-minute average wind. The shorter the wind averaging time, the stronger the reported winds will be. The adjustment factor would be approximately 0.90, which means if a buoy measures 80-mph eight-minute average winds, the one-minute average wind would be about 89 mph.
A more significant bias in the buoy data is the insanely severe ocean conditions that it’s reporting from. Waves in a major hurricane can be as high as 50 feet, and consequently, a buoy experiences very large crests and troughs as the hurricane passes over. When a buoy is on the crest of a wave, it is exposed to the full force of the surface winds, but when it is in the trough of a wave, it is going to be sheltered from the strongest winds. These weaker winds measured in the trough of a wave get averaged into the eight-minute averaging period measured by the buoy, which therefore gives the buoy’s estimated wind speed in a hurricane a low bias.
Surface stations also have significant measurement challenges in hurricanes.
Often during strong wind speeds, the anemometers break. Storm surge can also wash away weather stations before the strongest winds come ashore.
Importantly, a hurricane’s wind field is a wide swath, and the strongest winds may only be found in a small region of the hurricane. The number of surface stations in any area struck by a hurricane is likely not dense enough to accurately measure the strongest winds. For example, one 2014 study found that on average, “a single perfect anemometer experiencing a direct hit by the right side of the eyewall will underestimate the actual peak intensity by 10-20% percent. Even an unusually large number of anemometers (e.g., 3-5) experiencing direct hits by the storm together will underestimate the peak wind speeds by 5%-10%.”
The number of surface weather stations reporting hurricane-force winds, even in notoriously strong United States landfalling hurricanes are surprisingly small. For example, in NHC’s post-storm report on Hurricane Katrina (2005), a Category 3 hurricane on the Saffir-Simpson Wind Scale, only five surface weather stations reported sustained hurricane-force winds, with the strongest sustained hurricane-force winds reported being 86 mph. Many of the surface stations reporting the strongest winds were also flagged by NHC as being incomplete, indicating failure of the station before the strongest winds likely occurred. For reference, NHC estimated Katrina’s Louisiana landfall to have had maximum winds of 125 mph and its Mississippi landfall to have had maximum winds of 120 mph.
The peak winds in a hurricane are confined to a small region of the storm called the eyewall, which is the ring of thunderstorms that surround the eye. Beyond the eyewall, the wind speed drops off relatively quickly.
In the case of Hurricane Matthew, while the southeast United States suffered significant flooding damage due to both storm surge and heavy rain, the east coast of Florida dodged a huge bullet. Had Matthew tracked 50 miles farther to the west, the eyewall of the storm would have come ashore, causing much more extensive flooding as well as significant wind damage.
In any case, Matthew’s strongest winds would likely not have been measured by a weather station. The National Hurricane Center provides the best analysis that science can offer.
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Thanks for doing this post and responding to comments. Quite informative.
Dr Klotzbach,
I don’t disagree with what you are saying, my concern is the the wind velocities constantly reported are not what one expects at ground level. NHC should also report and predict the ground level velocities which are more important from the wind destruction and safety viewpoint. Survival at the reported high velocities is near impossible as one News caster reported “children will die” For emphasis, below an earlier comment is repeated.
“There are industry recognized groups of engineers that look at the wind data and have specified the design wind velocity for every portion of the US and the structure design wind velocities are less than the NOAA reported 165 MPH velocities. The maximum design velocity is 150 mph in the Gulf which reduces to 120 mph in the NY Harbor region. See document below.
https://law.resource.org/pub/us/cfr/ibr/003/asce.7.2002.pdf
These are 3 second gusts at 33 feet above ground level and the design formulas clearly adjust the load for the elevation. Look at page 37 for a map of the East Coast. I am sure these are conservative and represent the best estimate for establishing safe structural design.
Since the Max wind velocities (at possibly 10,000 ft.) are reported and people see the ground velocities from other sources, one will become suspect that the much higher velocities are hyped. NHC and NOAA should recognize the misrepresentation and make a correction to the information they present rather than trashing the messenger.
As an engineer involved in the design of structures, I have known for years, that the reported velocities do not occur at ground level since essentially no commercial structure would survive as the associated forces on the structure are proportional to the wind Velocity squared.
While there is criticism directed at Drudge, would you also expect a correction from the same organizations to a presidential candidate claiming that Matthew was worse because of Global warming although data indicates otherwise? Do you agree with that candidate’s statement statement?
Flight level winds are not what is utilized for NHC’s intensity estimates. These flight level winds are just one of several tools that NHC utilizes in its assessments. Also, remember that NHC is reporting the maximum one-minute sustained wind at 10-meter height anywhere in the hurricane. Thus, unless your building is well-removed from any trees or other terrain impacts, you aren’t going to see the strongest winds.
While NWS stations are few and far between, networks of weather stations like Weather Underground can help to fill the gaps. However, most of these stations aren’t likely to have anemometers that are 10 meters high. For example, in my neighborhood, my HOA would not be happy if I decided to put a 10-meter high anemometer!
Regarding TCs and climate change, here’s my most recent peer-reviewed publication on the topic:
http://tropical.atmos.colostate.edu/Includes/Documents/Publications/klotzbachlandsea2015.pdf
“The Information Age”
We got these satellites now! Didn’t use to have them. When libs are in charge, they like to take advantage of opportunities such as these to exaggerate their lib claims. Lib media loves it.
No story here, anyone able to think their way out of a wet paper bag already knows this…
words do means things…”maximum sustained winds” are NOT the peak found during the one minute of observation that reading is a “GUST” the MSW is the LOWEST reading during that minute, the lowest reading is the maximum SUSTAINED wind…….
Hours before Drudge’s comments on over-hyping appeared, I was online tracking the available buoy and land-based wind measurements in real time, as the hurricane moved through the Bahamas. On one of my screens I had the radar picture. Having spent many months of my life sailing through these waters, I am familiar with the water depths and land configurations in all of these islands. All of the instrumentation wind-speed maxima (available in real-time online) were far, far below the Category 4 levels being forecast during those moments, as I compared the radar eye-wall positions with the instrument readings on Andros, Berry Islands, Bimini and Grand Bahama, as well as from buoys. (Some of the latter were at locations in the lee of the land, or otherwise were not likely to be sheltered by extremely high waves). Drudge’s comments confirmed exactly what I had seen.
A few days after Hurricane Matthew I drove down the U.S. East Coast (from the Chesapeake to the Florida Keys) and saw storm damage, at the worst, consistent with 35-45 knot peak gusts.
I have a background in geophysics and when I first read (in the New York Times) a version of the above article, I was hoping to see an expert retrospective analysis of these same specific instrumentation data points, with a comparison of the forecasts and some explanation of the huge actual discrepancies in eyewall maxima (typically 45-55 knots rather than 120-130 knots). Instead, what I see in the article is apologetics, hand-waving and models, with little actual data. My worst suspicions are confirmed.
Well sometimes it seems this truck driver and some in science have a great deal in common.
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Your observations are correct. Typical plot of winds show Mathew was below hurricane force.
Eg. http://tinyurl.com/hbmobbr
should shows the Charleston, SC winds during Mathew much less than claimed by the NHC.
All of the NDBC buoys off the US coast recorded consistent sustained winds in the 40 knot range. Two exceptions, the St. Augustine station SAUF1 recorded 55 knot sustained winds maximum.
Also, Diamond Shoals, North Carolina (NDBC Station 41025) recorded 52 knot sustained winds.
Land stations showed consistently lower winds compated to offshore buoys.
The bahamas station SPGF1 recorded 68 knot sustained winds before it failed, but the plot of the winds from that station showed it was likely that any later winds were not greater much greater. Also, SPGF1 is not a buoy. It’s a land tower with anemometer height of 9.8 meters. Mathew was Category 1 over the Bahamas.
There are peer reviewed papers that analyze and compare buoy data to other data. For example, Gilhousen 1986 tests the quality and accuracy of the offshore buoy observations.
http://journals.ametsoc.org/doi/abs/10.1175/1520-0426(1987)004%3C0094%3AAFEONM%3E2.0.CO%3B2
The bottom line is that the buoy based anemometers are reliable, thats why they have been out there for decades. The photos of damage confirm the winds measured by the buoys and surface stations.
Another example of NHC claimed winds above reality is when Mathew passed directly over NDBC 42058 located south of Haiti that showed peak sustained winds of 65 knots at the same time that the NHC was claiming 125 knots. A time plot of sustained winds recorded by that buoy clearly show the eyewall on approach, the drop as the eye passed over, and eyewall winds on the trailing side. There is no possible explanation for that buoy being 60 knots too low. The NHC claims are not confirmed by reliable surface measurements or surface damage.
OK, so a Category 1 hurricane overturned cars in Freeport?
https://twitter.com/donavoncurtis/status/784489432816685056
AMS studies show that winds typically have to be at least 115 mph to overturn a mid-sized sedan. Also, if you look at the background of the same picture, palm trees are virtually completely toppled. While it’s hard to tell for certain what type of palm tree those are, sabal palms are typically only completely felled by Category 4/5 hurricanes.
Tetragrammaton – great to see your real life observations and comparisons.
Rich.
When Matthew was reported to be a major hurricane, its maximum winds were not onshore in Florida. Given your background in geophysics you would understand that assuming the pressure was 940 mb and that Matthew was not an extraordinarily large storm, you would have to have stronger winds than 45-55 knots to equal the pressure gradient force.
Here’s max wind gusts from TWC.
Cape Canaveral, Florida: 107 mph (on an elevated tower at 54 feet above the ground)
Tybee Island, Georgia: 96 mph
Jennette’s Pier, North Carolina (Outer Banks): 91 mph
Daytona Beach, Florida: 91 mph
Hilton Head Island, South Carolina: 88 mph
Jacksonville Area: 87 mph
South Ponte Vedra Beach, Florida: 84 mph
Duck, North Carolina: 83 mph
Beaufort, South Carolina: 83 mph
Fort Pulaski, Georgia: 79 mph
Folly Beach, South Carolina: 76 mph
Oceana NAS, Virginia: 75 mph
Myrtle Beach, South Carolina: 74 mph
Savannah, Georgia: 71 mph
Melbourne, Florida: 70 mph
Charleston, South Carolina: 69 mph
Florence, South Carolina: 67 mph
Lumbertgon, North Carolina: 66 mph
Fayetteville, North Carolina: 62 mph
Sumter, South Carolina: 61 mph
As I’ve stated several times before, it is very hard for a single surface station to sample the maximum 10-meter wind in a hurricane.
Why show only gusts?? Show the sustained wind speed data for those same stations. I was watching the data in real time, no sustained winds reaching over 56 knots at any surface based anemometer. Not just the majority of stations, all the stations in the path of Mathew show the same sustained wind speeds from Florida to North Carolina.
think of a race car going around an oval track….obviously it hits higher speeds on the straights and slower in the turns, so its maximum sustained speed would be the LOWEST reading on the curves, NOT the maximum on the straight(GUSTS).
One real important factor here is the effect of over-hype, but also the fact that peoples own experiences with claimed wind-speeds vs real-wind speeds can lead to real deadly mistakes.
Back in the day, when I was very young, we had to regularly look at the wind-chill numbers to dress appropriately. Lots of these numbers made little sense but over time I got to understand them. A couple of real close calls on frostbite and deip body chill was enough to respect the numbers and be happy I lived through my exposure. But the fact is, IT IS HARD to understand QUANTITATIVELY what they mean. When people hear difficult to understand numbers and then experience something far less, this will lead to deadly consequences and distrust of the reporting authority.
Missing the predictions badly just makes NHC look bad. But the effect of the apparent low winds on land and the reporting of higher winds gusts by the NHC makes us think we should perhaps not trust them.
An important consequence of them missing it. As the next time around LOTS of people may try to ride it out cuz they did the last one. Trouble. Maybe they should do a post anaylsis session after each hurricane and then admit when it appears they goofed or show how accurate they were.
Dr. Klotzback… I have been a meteorologist nearly all my life and I am now 71. I was a professional meteorologist for over 40 years and am a Fellow of the AMS. I have come to appreciate your work and that of Dr Gray more so as the years have gone by. However, as mostly an observer of hurricanes (I have only personally experienced the effects of Hazel, Agnes and David) it has been my experience that rarely have observed wind speeds matched those of the NHC bulletins, especially so with Matthew.
You keep mentioning how bad conditions would have been had Matthew been 50 miles farther to the west. Granted they would have been worse but would it have been the catastrophe we have been led to believe? After all, the eye wall did pass over Nassau (did it not?) and as at least a category 3, maybe 4. But look at the damage described in this article from a comment above by Frank N. http://eleutheranews.com/?p=6765
The article states “NASSAU, THE BAHAMAS – The 47 marina and allied members of the Association of Bahamas Marinas are open for business and are anticipating a busy winter season, almost all members having experienced no significant damage during the recent hurricane Matthew.” How can this be if the winds were truly as high as NHC reported?
Prior to the storm, Joe Bastardi frequently mentioned this was a worst case scenario for Nassau. Well, no, that’s not what happened. So next time a storm of this supposed intensity is forecast to strike, how many people will disregard the warnings based upon what happened this time?
I don’t for a minute believe NHC is inflating wind speed numbers but I do believe the current state of warnings does not give residents a realistic picture of what may occur. I applaud your attempt to explain the uncertainties involved in determining wind speeds but I don’t believe it resolves the disconnect between what people see with their “lying eyes” and what the bulletins are stating. Good luck with that by the way.
A well-reasoned comment, it speaks to “warning fatigue” which is just as dangerous in hurricane situations as the hurricane itself.
There was some pretty significant storm damage in Freeport. While I can’t quantitatively say exactly what kinds of winds are required to overturn cars, it’s certainly well into the sustained hurricane-force wind category.
https://twitter.com/donavoncurtis/status/784489432816685056
Given that all other cars are in parking spots, this was certainly done by the wind and not by water. The Bahamas have some very strong building codes, especially for their businesses. They are no stranger to major hurricanes. This is evidenced by the fact that the airport on Exuma measured a sustained wind of 119 mph and a wind gust to 144 mph, but yet according to that report, was ready for business just a few days later.
In the case of the United States, except for a few exceptions like Hurricane Andrew (1992), most damage in hurricanes is caused by water, not wind. Had Matthew tracked 50 miles further west, the storm surge would have been much higher, inundating many coastal communities. The difficult challenge with Matthew was that it was tracking parallel to the coast. A 50-mile track farther east, and it would have been a virtual non-event for the state of Florida. Several reliable models brought the storm onshore. In this situation, I don’t see how NHC could do anything differently than they did.
Neil Frank used to say that you have to evacuate three times for every one time that you need to evacuate. While hurricane forecasts are getting better, these storms aren’t happening in a lab where they can be forecast perfectly.
Is anyone arguing whether or not Matthew was devastating?
It doesn’t matter what category you call it, the damage in Haiti, the Bahamas, and the Carolinas was substantial. A category 3 hurricane has devastating wind speed. I’ve also seen Tropical Storms that have created substantial damage. Sandy was devastating even though it was no longer hurricane strength when it struck New Jersey.
The only question that I see has to do with trend analysis. If there is an upward bias to the measurements, then people who study the relationship between hurricane strength and climate change will be affected by this upward bias. Already we had people crying “climate change” about Matthew before it left Florida even though it was one of the first major hurricanes in a decade.
Thanks to everyone who has commented on this, very educational. However, I haven’t seen a comment about this:
“… one 2014 study found that on average, “a single perfect anemometer experiencing a direct hit by the right side of the eyewall will underestimate the actual peak intensity by 10-20% percent. Even an unusually large number of anemometers (e.g., 3-5) experiencing direct hits by the storm together will underestimate the peak wind speeds by 5%-10%.””
But from the abstract of the study:
“This study uses an observing system simulation experiment (OSSE) approach to test the limitations of even nearly ideal observing systems to capture the peak wind speed occurring within a tropical storm or hurricane.”
So are the anemometers really underestimating wind speeds, or has the data been adjusted to the model? Have the models been verified? Shouldn’t they actually be verified by the anemometers, or as others have sugggested, by the observed damage?
Details on the study here:
https://www.rsmas.miami.edu/users/dnolan/papers/NZU_winds_published.pdf
i appreciate your efforts, but it sure seems to me the term “sustained winds” is not even being discussed…..sustained means constant winds, NOT the highest winds in one quadrant… sustained winds SHOULD mean the highest wind that is constant in the entire storm center.
Averaging winds over the eyewall would be a meaningless quantity… In a sheared situation you could have 120 mph winds dominating on one side and 60 mph winds on the other side. To say that maximum sustained wind was 90 mph would not be helpful to anyone. That’s why NHC has the maximum sustained wind but also specifies winds in various quadrants.
where was averaging suggested? for certain claiming there is a sustained wind based on the maximum of a tiny portion of the storm is also meaningless…….bottom line for me is the public needs accurate info not hype and matthews winds were HYPE = nothing even close verified on the ground
The problem is not that modern techniques for assessing hurricane strength are inaccurate. Clearly they are more accurate. And when it comes to giving warning to people in the path of a Hurricane more accurate data can only be to the better. However these more accurate techniques were not available in the past. Would Matthew have been recorded as a 5 using the tools available in the 1940’s? Doubtful I’d say.
Better measurement techniques means that Hurricanes are probably assessed as being stronger today than the same Hurricane would have been in the past. And this biases the long term record.
When anemometers were the main way of recording wind strength they did sometimes record sustained (8 minute average) wind speeds of Cat 5 strength as hurricanes passed over them. If for all the valid reasons mentioned, these anemometers were underestimating then those Cat 5 Hurricanes of the past must have been absolute monsters. If ever such a monster hits us again I suspect the usual suspects will want to invent a Cat 6 to describe it, and claim that global warming has made Hurricanes worse.
Most older measurements from hurricanes are not from anemometers over the open ocean but from the Beaufort Scale used by mariners. I have not yet found a single measurement of sustained Category 5 winds from a hurricane in the United States. Anemometers were few and far between in 1935, Camille took out all anemometers within a ~50 mile radius of the coast, and Andrew’s top winds from a surface station were 146 mph (Category 4).
But yes, there are likely underestimates as you go back further in time with the Atlantic hurricane database. That’s why most climate studies for the Atlantic start in the 1960s when geostationary satellite should have captured most systems. Of course, the Atlantic also has very large natural multi-decadal cycles in hurricane activity that would make any trend detection hard to quantify.
beaufort measurements from ships are based on the ships anemometer. We have had those on ships since the 15th century. They work!
That is incorrect David. Ship anemometers were very rare prior to 1950:
http://journals.ametsoc.org/doi/pdf/10.1175/1520-0442(1990)003%3C0113:OTIHMW%3E2.0.CO%3B2
The original Beaufort scale was based on gradations of sea state from calm to hurricane-force.
Phil I doubt any sailor going back to the 1500’s would sail without an anemometer. This is a reporting issue vice an equipment issue. Even the paper discusses the form issue and I would say that many periods are devoid of military weather reports due to the inclusion of location which is frequently a piece of information military vessels just do not report without some prodding. Prior to 1950 your dealing with a variety of issues that have nothing to do with the weather or instrumentation on ships.
The point is not windspeed per se for climate change, but wind speed RELATIVE to previous storms. If new methods are used to upgrade hurricanes, a “fix” must be applied to the historical data.
Apples and oranges. The msm and alarmists call hurricane Matthew a Cat 4 or 5, though it made landfall at Cat 1. Anecdotal bad weather now equals historical measurements when dending AGW.
Global warming is a witch; a lack of proof is not proof, once again, of a lack of witches.
Agreed, which is why Chris Landsea at NHC and I looked at trends in the strongest storms since 1990 globally, since prior to then there are likely underestimates due to poor satellite resolution:
http://tropical.atmos.colostate.edu/Includes/Documents/Publications/klotzbachlandsea2015.pdf
However, while we should never underestimate the impact of a storm nor should they be hyped, in 2013 the BOM in Australia hyped a storm near Rockhampton from Cat 2 up to cat 5 that’s a hype of 8 TIMES – damage was relatively minor because surface wind speed was only category 1 – 2. The result is that next time a cat 5 storm is bearing down on them they won’t take it seriously enough. The BOM was crying wolf.
So it is with Matthew, Drudge is right to call it out, it was misclassified by 10m surface wind velocity. People need accurate information and not be desensitized to cat3+ storms by the weather people hyping low category storms. What the satellites show was not accurate and Matthew was probably never a category 5 in terms of surface wind.
That doesn’t mean it wasn’t dangerous, just that we were being lied to about how dangerous
Yep. Trees still standing, and they show a picture of an old house without a roof to talk about the “devastation.” Ignoring that in the background was a new house that not only didn’t lose its roof, it didn’t even lose its SOLAR PANELS!! That was no Cat 5.
And what’s worse is that despite having a weather station in the path of an eye, the BoM disappeared 3 days of data because they only showed Cat 2 readings (I had a screenshot before all the data went away). It was physically impossible to escalate from Cat 2 to Cat 5 in a couple of hours – it didn’t happen, and the data shows is didn’t happen as does the distinct lack of damage.
Then they did it again in the Peoples Republic of South Australia. “Unprecedented” “50 year storm event.” One that didn’t show a gust over 115km/h (just 60kt) on the mainland, when Woomera had recorded 167km/h in 1979 which was a lot less than 50 years ago.
Next they’re going to delete the records from Woomera to make their claim true.
See also Typhoon Haiyan. I saw people filmed on their roofs, hanging on for dear life while keeping out of the certainly fatal storm surge that sent waves of debris-laden seawater through their streets. Tragically, they probably died. But the point is they were out there with a fighting chance – there is no way a guy hangs onto his roof in the “strongest storm in history!”
The whole hoax came out of the BBC reporting a gust as “mph” instead of “km/h” and someone claiming a world record on the strength of a typo. 4 years later, the typo has become the official record and anyone saying it was a Cat 4, weakening to a Cat 3 at landfall. 99% of the damage filmed was from storm surge – actual wind damage was limited.
I’m not accusing the NHC of the same thing – Mathew was a very big hurricane and had it turned left Floridians were in heaps of trouble.
I have no problem with the view that current data is accurate, thanks to better recording methods that can assess the entire storm rather than relying on a direct hit at peak speed on an anemometer that doesn’t break in half. Fine, the wind speed recorded was a Cat 4, so it was a Cat 4.
My problem is not comparing like for like, and deducing that modern events are unprecedented / increasing / weirded.
If the 1920’s had a 10 year period between Cat 3 landfalls hitting a weather station, then that’s don’t take a radar reading 100km between stations and claim it’s accelerating. Either scale up the history (like they adjust the past temp data), or record “weather station only” datasets to allow inter-generational comparisons and just compare old to old data.
Well, your mileage may vary. Because I do have a problem with current data. Dr. Klotzbach says that the NHC can estimate different wind speeds in each quadrant. Well, that’s great, so when a quadrant passes over a buoy, like 42058 in the article, the buoy’s gusts (being generous and discounting sustained wind because of swells) should at least match up to those speeds. Did they? No.
But then, it was only one buoy. Perhaps the winds saw it and, taking pity, slowed down. Just like, before the recent El Nino, the global warming heat was apparently going into the deep sea without touching the surface… It’s all alarmingly bad, but we just don’t have any witnesses to prove it.
Rich.
Well, I think people being unreasonable is as much at fault as any external cause for alarm fatigue. Human beings are famously bad at understanding and managing probabilities and risks, and our biases often hinder us in recognizing good information when we see it.
I am sorry, but I am with Matt Drudge on this one. It wasn’t that the ground stations measured 10-20% less. The largest gusts were 1/2 of what was claimed and some weather stations got pretty close to the center of action.
I think the issue might be with the estimate rather than the ground stations. But never doubt the simulations/computer models.
I’ve stated in my response several times that these are surface wind estimates, not winds recorded at any particular level. I certainly have not “ducked” the question as you posit.
You can track all aircraft reconnaissance through a nice viewable format at Tropical Tidbits:
http://www.tropicaltidbits.com.
Aircraft recon reports winds measured at flight level (10,000 feet) along with estimates of surface winds from the SFMR instrument. You can also get the data reported by individual dropsondes.
Does anyone here remember how the “science community” responded during the wild accusations and claims that were made at the time of Hurricane Katrina? To the weather-people: you reap what you sow.
Here’s a paper I wrote in 2006… following the very active 2004/2005 Atlantic hurricane seasons. I hardly find this hype.
http://onlinelibrary.wiley.com/doi/10.1029/2006GL025881/epdf
Exaggerated estimates are the math version of dude with umbrella standing in front of a blue screen with sprinkler and fan aimed at him.
Andrew
marque2,
I agree with you. I personally think NOAA/NHC report the maximum recorded velocity at any elevation rather than the velocity at ground level. I have raise this question with the writer several times and he seems to duck the question.
I have offered as evidence the design winds that engineers use for the east coast are lower than the reported NOAA hurricane wind velocities and has various factors for elevation adjustments and exposures, and the author seems to duck the question. These numbers are not different because of adjacent structures as suggested since many structures are not protected by other buildings, and rise to rather high elevations. At the risk of repeating again:
See document below.
https://law.resource.org/pub/us/cfr/ibr/003/asce.7.2002.pdf
These are 3 second gusts at 33 feet above ground level and the design formulas clearly adjust the load for the elevation. Look at page 37 for a map of the East Coast. I am sure these are conservative and represent the best estimate for establishing safe structural design.
Note that these are 3 second gusts which is a shorter timeframe than the NOAA reported timeframe. These folks .who establish this have a lot of responsibility to keep us safe and don’t take the responsibility lightly.
NHC’s reported winds are at the surface, not at any level in the storm. I suggest following their aircraft reconnaissance reports in real-time. They report winds both at flight level (10,000 feet) as well as at the surface as estimated by the SFMR instrument.
The eyewall of Matthew did not come ashore in Florida when it was a Category 3/4, so I wouldn’t have expected to see 100+ mph winds on land. As I’ve posted in several other replies, there were wind gusts reported in the 80-90 mph range with Matthew’s landfall in South Carolina, which is consistent with a Category 1.
As far as its strength through the Bahamas, Exuma airport reported a maximum sustained wind of 119 mph and gusts to 144 mph. Freeport’s station failed before the center of the storm came ashore, but as I’ve shown earlier in the discussion, cars were flipped over by the wind. Since you’re the engineer, you can tell me what kind of wind it requires to flip a car, but it’s certainly in the Category 3/4 range.
Dr Klotzbach
Thanks for your reply
FYI I have never judged the accuracy or motive of the information provided by the NHC or NOAA, I was skeptical on the media and NOAA storm descriptions reported wind velocities based on experience and the link I provided from the asce as to how they relate to surface winds used for design of structures. If I understand you correctly the velocities are “ground Level”?
“NHC’s reported winds are at the surface, not at any level in the storm.”
So are you saying that when I hear the Hurricane is packing 145 mph winds these are at the surface somewhere, recognizing they reduce further away from the center?
Or is the surface wind velocity reported elsewhere? If so please advise where I should look to find it. As a boat owner it is important to me to make decisions to try to protect property.
I don’t claim to be an expert to interpret wind velocities or as one who develops the ASCE design velocities used throughout the country, I just use them for structural calculations and would like to understand any differences. FYI the ASCE design velocities are for 3 second gusts and vary throughout the elevation of a structure and appear to be circa 10% less than velocities reported.
FYI I looked at velocities to flip a car which is reported as “115 to 180 MPH to flip a car”.
I apologize If anything I said appears to be derogatory, I was just trying to understand whether the reported velocities should be expected at ground level and why different than the ASCE in some cases.
Appreciate your reply.
The official NHC forecast is for winds at 10 meters above ground level. There a ton of graphical products available from NHC which highlights the wind field for each storm:
http://www.nhc.noaa.gov/archive/2016/NICOLE_graphics.shtml
These products are excellent, as they can highlight significant storm asymmetries. For example, in sheared storms, hurricanes may have very little (if any) hurricane-force winds in specific quadrants of the storm. Levi Cowan at Tropical Tidbits (http://tropicaltidbits.com) has a great aircraft reconnaissance page which displays real-time flight level wind measurements by the Hurricane Hunter plane in real-time.
Dr. Philip Klotzbach, thank you for your guest post here as well as your comments. But you seem to be trying to work a PR scheme in the interest of the NHC.
The past 7 years or so hurricanes have been over-hyped to an unprecedented degree by both the NHC and of course the press. Only a fool would believe what the press reports but I would expect at least some degree of the truth from the NHC. I have followed in real time several reported hurricanes and tropical storms in the Atlantic/Gulf basins the past several years. Two in particular were Irene and Sandy. Had family in the Wilmington, NC landfall area and multiple tabs open on my computer which I monitored for hours. Irene was waaay over-hyped. Then along comes Sandy and it was the same business as usual (over-hyped) from the NHC. Feel free to look into the WUWT archives as Sandy traveled up the Atlantic seaboard as I (eyesonu) documented weather station reports/data from many locations that were in extreme conflict with the NHC. Just for fun I was also tossing in weather /data from some city on the great lakes that was not under any influence of Sandy for comparison.
You have done well in your PR efforts here but I’m not buying it. Good luck with any grants you may be seeking as your efforts here will look good on your resume.
Sandy was a rain and surge producer, not a wind event. NHC never stated the winds were the main problem. I’m sure those living in New York/New Jersey would beg to differ that Sandy was over-hyped. $75 billion dollars in damage is hardly a small event.
I have always felt that if it hit somewhere further from where the press and government are ensconced it would have never been crowned with the made up nomenclature of “super storm” no matter how populated or how much damage it did at landfall.
That is the type of overhype that I believe many of us in flyover country often perceive. Anything that ever happens is worse when it occurs along the I-95 corridor from the NYC area to the DC area. Just like the hype when they had a high in the mid 90s in Central Park this summer. That wasn’t even close to a record but you would have thought it was life threatening for the general masses the way it was covered.
Have you looked at earlier notorious hurricanes? Katrina’s maximum sustained wind on U.S. soil was 86 mph… was that also NHC hype?
I suggest a thorough search of maximum sustained winds in other hurricanes. In Category 5 Camille, there were no anemometers left within 50 miles of the coastline after the storm.
I am surprised that everyone is so fixated on anemometers and ignores constant wind reports from aircraft, as well as estimates from the SFMR and radar. There’s a reason that NHC uses these and just doesn’t depend on surface observations. For example, in Hurricane Ike, all NWS weather stations within close proximity to landfall failed.
Are you saying that they are deliberating fudging the data, or just that there are massive wind reductions from 10,000 feet to the surface. If the former, that displays considerable paranoia and if the latter, you are ignoring many published studies as well as the dropsonde data that helps establish the appropriate reduction from flight level to the surface.
But if you want to declare yourself the expert, so be it.
Phil Klotzbach said:
“I am surprised that everyone is so fixated on anemometers and ignores constant wind reports from aircraft, as well as estimates from the SFMR and radar.”
It’s partly because many people have painted themselves into a corner with uninformed criticism. To climb back down from their position is to acknowledge that they didn’t have sufficient understanding to take such a position in the first place. The belief that the NHC and other organizations are deliberately trying to mislead the public is a deep part of many peoples identities, and to acknowledge otherwise is a much bigger step for them than simply acknowledging they were wrong about some specific scientific detail.
Dr. Klotzback
Do you deny that there is a natural tendency for inflation of both incidence and severity as compared to past records due to the march of technology in detecting and measuring TCs?
NOAA certainly recognizes such inflation in the US tornado count record and is attempting to adjust for it.
http://www.spc.noaa.gov/wcm/adj.html
BTW I notice that their adjusted count for this year is very close to that of the historic minimum set in 2013.
Phil there is a huge difference between anemometers reporting low numbers and being destroyed. only a very small number of anemometers died to Mathew. where as Camille, Andrew and Katrina killed them all. You need to rethink what your saying.
David Riser said:
“Phil there is a huge difference between anemometers reporting low numbers and being destroyed. only a very small number of anemometers died to Mathew. where as Camille, Andrew and Katrina killed them all. You need to rethink what your saying.”
Camille, Andrew and Katrina made landfall. Mathew didn’t. Why would you expect similar damage to anemometers from a hurricane that didn’t make landfall?
Sorry for misspelling your name. It was completely unintentional.
Sure, I agree with you that there is a natural tendency for inflation in TC numbers, especially for weak named storms. Chris Landsea did an excellent job documenting this in a series of studies at NHC. When it comes to stronger hurricanes, they are probably reasonably consistently observed in the Atlantic since the mid-1960s, given that we’ve been using aircraft reconnaissance to fly most of the stronger storms. Underestimates likely plague most other global TC basins until ~1990. So, when looking at metrics like Accumulated Cyclone Energy, I would say that values since the mid 1960s probably aren’t too far off from reality in the Atlantic. Prior to that, there are likely underestimates. Gabe Vecchi and colleagues looked at ship traffic prior to 1966 to try and estimate “missed” hurricanes. When you apply these underestimates, you see no trend in hurricanes since the late 1800s. Similarly, when I assume that each missed hurricane generated ~10 ACE units (equivalent to the average observed Category 1-2 hurricane from 1966-2015), you get no trend in ACE since the late 19th century.
With regard to failing anemometers, Dr. Klotzbach wrote:
“I suggest a thorough search of maximum sustained winds in other hurricanes. In Category 5 Camille, there were no anemometers left within 50 miles of the coastline after the storm.
“I am surprised that everyone is so fixated on anemometers and ignores constant wind reports from aircraft, as well as estimates from the SFMR and radar. There’s a reason that NHC uses these and just doesn’t depend on surface observations. For example, in Hurricane Ike, all NWS weather stations within close proximity to landfall failed.”
Back on April 12, 1934, the weather station on Mt. Washington, NH, recorded a peak wind gust of 231 miles per hour. “The anemometer used to record the record wind was a heated anemometer designed special for Mount Washington. It was constructed in Cambridge MA, and tested in the wind tunnel at the Guggenheim Aeronautical Laboratory of the Massachusetts Institute of Technology in Boston.
“After the wind measurement, the anemometer was run through a number of tests by the National Weather Bureau and the historic measurement of 231 mph was confirmed to be a valid reading.”
Source: https://www.mountwashington.org/about-us/history/world-record-wind.aspx
My comment and question for Dr. Klotzbach: For the general populace, surface winds are the only relevant measure, as they cause the damage. Why is there not in place in “Hurricane Alley” a comprehensive network of “special” anemometers, a la, Mt. Washington, designed to measure and withstand Hurricane Camille – force wind gusts?
I think the real problem with anemometer failure is that in most of the strongest storms, storm surge takes them out (as opposed to the wind). Of course, in the case of Hurricane Andrew (1992), winds did take out the anemometer mounted by NHC.
While there isn’t a special anemometer network in Hurricane Alley is a bit curious to me as well. I will note in the case of the Mount Washington Observatory, it is continuously manned by a team of observers. These observers go to nearly heroic efforts during the winter months to keep the anemometer clear of rime ice. I encourage you to check out the videos that they post in the winter. It’s pretty crazy how intense those winds are in the winter.
The Mount Washington Observatory is also a non-profit which has additional funding beyond that coming from NOAA.
Phil Klotzbach ,
Where are you?
That was supposed to assure us ? Color me unimpressed … Basically the author showed that they have no way of telling a normal person not living at 10,000 feet in the path of a storm what the expected winds could be … So basically useless … Typical a** covering academic nonsense
Did you actually read the article? There have been many studies that have looked at adjustments between 10,000 feet and the surface. They also utilize dropsondes to measure winds descending from 10,000 feet to the surface. The SFMR utilizes the sea state to estimate winds at the surface. The use of the sea state to estimate surface wind speed has been a technique employed for over 50 years. Radars can also be used to quite accurately estimate surface winds close to land.
On another note, they used to fly aircraft much lower than 10,000 feet into hurricanes, but a Hurricane Hunter plane in Hurricane Janet (1955) crashed into the sea when it attempted to penetrate Janet’s eyewall at 700 feet, which is when the aircraft decided to fly considerably higher.
https://weather.com/storms/hurricane/news/hurricane-hunter-plane-crash-janet
But if you want to knock 60+ years of research by hundreds of scientists as “academic nonsense”, that is your decision.