The mean annual damage from hurricanes in the US is 9. Hurricane damage varies greatly from year to year, depending on the number and strength of hurricanes making landfall, but there does not seem to be a long-term trend in adjusted damage over the last century.
There is very little association between the physical size of a hurricane and its intensity. A big hurricane does not have to be an intense one and vice versa. The damage a hurricane can cause is a function of both its maximum sustained wind and the extent of the hurricane force winds. A broad, weak storm may cause as much damage as a small, strong one. It is false to think that damage is linear with wind speed, that a mph winds will cause twice the damage as a mph winds.
The relationship is exponential, and not linear. A category 5 storm could cause up to times the damage of a category 1 hurricane of the same size. References: Weatherford, C. Pielke, Jr. Forecasting, 13, pp. Just as every person is an individual, every hurricane is different. So every experience with such a storm will be unique. The summary below is of a general sequence of events one might expect from a Category 2 hurricane approaching a coastal area. What you might experience could be vastly different.
Hurricane forecasters estimate tropical cyclone strength from satellite using a method called the Dvorak technique. Vern Dvorak developed the scheme in the early s using a pattern recognition decision tree Dvorak , If infrared satellite imagery is available for Eye Patterns generally the pattern seen for hurricanes, severe tropical cyclones and typhoons , then the scheme utilizes the difference between the temperature of the warm eye and the surrounding cold cloud tops.
The larger the difference, the more intense the tropical cyclone is estimated to be. CI numbers have been calibrated against aircraft measurements of tropical cyclones in the Northwest Pacific and Atlantic basins.
On average, the CI numbers correspond to the following intensities:. Note that this estimation of both maximum winds and central pressure assumes that the winds and pressures are always consistent. The reason that lower pressures are given to the Northwest Pacific tropical cyclones in comparison to the higher pressures of the Atlantic basin tropical cyclones is because of the difference in the background climatology.
The Northwest Pacific basin has a lower background sea level pressure field. Thus to sustain a given pressure gradient and thus the winds, the central pressure must accordingly be smaller in this basin.
The errors for using the above Dvorak technique in comparison to aircraft measurements taken in the Northwest Pacific average 10 mb with a standard deviation of 9 mb Martin and Gray Atlantic tropical cyclone estimates likely have similar errors.
Thus an Atlantic hurricane that is given a CI number of 4. These would be typical ranges to be expected; errors could be worse.
However, in the absence of other observations, the Dvorak technique does at least provide a consistent estimate of what the true intensity is. While the Dvorak technique was calibrated for the Atlantic and Northwest Pacific basin because of the aircraft reconnaissance data ground truth, the technique has also been quite useful in other basins that have limited observational platforms. However, at some point it would be preferable to re-derive the Dvorak technique to calibrate tropical cyclones with available data in the other basins.
Lastly, while the Dvorak technique is primarily designed to provide estimates of the current intensity of the storm, a 24 h forecast of the intensity can be obtained also by extrapolating the trend of the CI number. Whether this methodology provides skillful forecasts is unknown. References: Dvorak, V. Dvorak, V. Fitzpatrick, P. Knaff, C. Landsea, and S. Forecasting , 10, pp. Martin, J. Forecasting , 8, pp.
Each method has advantages and draw backs. Post-storm analysis of storm surge requires resolving differences in what each measures in order to find the best approximation of the surge heights. A network of long-term, continuously operating water level stations located throughout the U. They are created by foam, seeds, and other debris.
Survey crews deploy after a storm, locate, and record reliable high-water marks. GPS methods are used to determine the location of these marks, which are then mapped relative to a vertical reference datum. Pressure Sensors USGS These are temporary water-level and barometric-pressure sensors which provide information about storm surge duration, times of surge arrival and retreat, and maximum depths.
Some important terms from that glossary are below. Hurricane Watch — A Hurricane Watch is an announcement that hurricane force winds are possible within the specified area in association with a tropical cyclone. A hurricane watch is issued 48 hours in advance of the anticipated onset. Hurricane Warning — Hurricane warnings are issued 36 hours in advance and are announced when hurricane force winds are expected somewhere within the specified area in association with a cyclone.
This warning can remain in effect in the face of other hazards, such as flooding even if the winds drop to below hurricane force. Advisory — An advisory contains all tropical cyclone watches and warnings in effect along with details concerning tropical cyclone locations, intensity and movement, and precautions to be taken.
Maximum sustained wind — This is determined as winds that last for an average of at least one minute at the surface of a hurricane or about 33 feet 10 meters. Gusts — are classified as a second burst of wind higher than the maximum sustained wind. Storm Surge Watch — A storm surge watch is the possibility of a life-threatening inundation from rising water moving inland from the shoreline, and it is usually issued 48 hours from the anticipated event in association with an ongoing tropical storm.
Storm Surge Warning — The danger of a life-threatening inundations from rising water moving inland, and usually issued 36 hours in advance of the event in association with an ongoing tropical storm.
Storm Intensity — Hurricane intensity refers to the amount of energy a hurricane is carrying with it. Hurricane intensity and size are not closely related. Reference: Powell, M. Houston, and T. The Atlantic Oceanographic and Meteorological Laboratory AOML supports these organizations by doing hurricane research with both observations and model experiments in order to provide guidance and integrate new technology into the forecast models.
These experimental models are tested rigorously and submitted to the NCEP for verification before they are integrated into the operational models and sent to the NHC for use in the public forecast. There are a number of different seasonal forecasts currently being issued for various basins. Some of these are fairly new, while the oldest and most well known Prof.
The major hurricane track forecast models run operationally for the Atlantic, Eastern Pacific, and Central Pacific hurricane basins are:. The full list of models used in the Atlantic and Eastern and Central Pacific is available to download here.
Various types of consensus models ensemble means are available from these models. Despite the variety of hurricane track forecast models, there are only a few models that provide operational intensity change forecasts for the Atlantic and Eastern and Central Pacific basins:.
Information on the performance of these models is available after each season here. References: Aberson, Sim D. Marks, D. Meteorological Center; Camp Springs, Maryland, 89 pp. Lord, S. Bender, M. Ross, R. Tuleya, and Y. Gopalakrishnan, S. Goldenberg, T. Quirino, X. Zhang, F. Marks, K-S Yeh, R. Atlas, V. Forecasting , 27, pp. Radford, A. Fiorino, M. Goerss, J. Jensen, E. Harrison, Jr. Jarvinen, B. NS NHC , 22pp. DeMaria, M. Forecasting , 9, pp.
The U. It was an ambitious experimental program of research on hurricane modification carried out between and The proposed modification technique involved artificial stimulation of convection outside the eyewall through seeding with silver iodide. The invigorated convection, it was argued, would compete with the original eyewall, lead to the reformation of the eyewall at larger radius, and thus, through partial conservation of angular momentum, produce a decrease in the strongest winds.
Modification was attempted in four hurricanes on eight different days. These promising results came into question in the mids because observations in unmodified hurricanes indicated:. For a couple decades NOAA and its predecessor tried to weaken hurricanes by dropping silver iodide — a substance that serves as an effective ice nuclei — into the rainbands of the storms. The experiments took place over the open Atlantic far from land. The idea was that the silver iodide would enhance the thunderstorms of a rainband by causing the supercooled water to freeze, thus liberating the latent heat of fusion and helping a rainband to grow at the expense of the eyewall.
With a weakened convergence to the eyewall, the strong inner core winds would also weaken quite a bit. Neat idea, but in the end it had a fatal flaw. This phenomenon makes it almost impossible to separate the effect if any of seeding from natural changes. No wonder the first few experiments were thought to be successes. A special committee of the National Academy of Sciences concluded that a more complete understanding of the physical processes taking place in hurricanes was needed before any additional modification experiments.
Reference: Willoughby, H. Jorgensen, R. Black, and S. There have been numerous techniques that have been considered over the years to modify hurricanes: seeding clouds with dry ice or silver iodide, reducing evaporation from the ocean surface with thin-layers of polymers, cooling the ocean with cryogenic material or icebergs, changing the radiational balance in the hurricane environment by absorption of sunlight with carbon black, flying jets clockwise in the eyewall to reverse the flow, exploding the hurricane apart with hydrogen bombs, and blowing the storm away from land with giant fans, etc.
As carefully reasoned as some of these suggestions are, they all share the same shortcoming: They fail to appreciate the size and power of tropical cyclones. For example, when Hurricane Andrew struck South Florida in , the eye and eyewall devastated a swath 20 miles wide. The heat energy released around the eye was 5, times the combined heat and electrical power generation of the Turkey Point nuclear power plant over which the eye passed. The kinetic energy of the wind at any instant was equivalent to that released by a nuclear warhead.
Human beings are used to dealing with chemically complex biological systems or artificial mechanical systems that embody a small amount by geophysical standards of high-grade energy. Because hurricanes are chemically simple —air and water vapor — introduction of catalysts is unpromising. The energy involved in atmospheric dynamics is primarily low-grade heat energy, but the amount of it is immense in terms of human experience.
About 80 of these disturbances form every year in the Atlantic basin, but only about 5 become hurricanes in a typical year. There is no way to tell in advance which ones will develop. Maybe the time will come when men and women can travel at nearly the speed of light to the stars, and we will then have enough energy for brute-force intervention in hurricane dynamics. Until then, perhaps the best solution is not to try to alter or destroy the tropical cyclones, but just learn to co-exist with them.
Since we know that coastal regions are vulnerable to the storms, building codes that can have houses stand up to the force of the tropical cyclones need to be enforced. The people that choose to live in these locations should be willing to shoulder a fair portion of the costs in terms of property insurance — not exorbitant rates, but ones which truly reflect the risk of living in a vulnerable region.
In addition, efforts to educate the public on effective preparedness needs to continue. Helping other nations in their mitigation efforts can also result in saving countless lives. Finally, we need to continue in our efforts to better understand and observe hurricanes in order to more accurately predict their development, intensification, and track.
References: Simpson, R. New York Acad. Frank, M. Corrin, C. Woodcock, A. Blanchard, C. Blanchard, D. NY Acad. Apart from the fact that this might not even alter the storm, this approach neglects the problem that the released radioactive fallout would fairly quickly move with the tradewinds to affect land areas and cause devastating environmental problems.
Needless to say, this is not a good idea. Now for a more rigorous scientific explanation of why this would not be an effective hurricane modification technique. The main difficulty with using explosives to modify hurricanes is the amount of energy required. The heat release is equivalent to a megaton nuclear bomb exploding every 20 minutes. In addition, an explosive, even a nuclear explosive, produces a shock wave, or pulse of high pressure, that propagates away from the site of the explosion somewhat faster than the speed of sound.
For normal atmospheric pressure, there are about ten metric tons kilograms per ton of air bearing down on each square meter of surface. In the strongest hurricanes there are nine. To change a Category 5 hurricane into a Category 2 hurricane you would have to add about a half ton of air for each square meter inside the eye, or a total of a bit more than half a billion ,, tons for a 20 km radius eye.
Hygroscopic refers to a substance that binds preferentially with water vapor molecules. Anyone who has used a salt shaker on a humid summer day understands- the salt clumps. The barrier to this method is the assumptions and uncertainties in such a project that would require extensive testing first. Some people have proposed seeding the inflow layer of a hurricane with granules of some hygroscopic substance.
The hope is that these granules will help form tiny cloud droplets, many more than would form naturally. There are several assumptions made in this chain of logic. The first is that there are too few cloud condensation nuclei CCN available naturally.
And lastly, it assumes that the increased burden on the updraft outweighs the increase in latent heat released when more liquid water reaches the freezing level.
If less water is precipitating out, then more will be freezing. Otherwise, you would expend a great deal of money and effort, but not change a hurricane sufficiently.
It has been proposed to drop large amounts of the substance into the clouds of a hurricane to dissipate some of the clouds thus helping to weaken or destroy the hurricane.
The argument was that the glop would make raindrops lumpy i. The foregoing effect is larger than anything one could hope to produce in the real atmosphere. Did they watch any unmodified clouds? Isolated Florida cumuli have short lifetimes, and these are just the ones an experimenter would logically pick. Accepting for the sake of argument that they actually did have an effect, the descriptions seem more consistent with an increase in hydrometeor fall speed and accelerated collision coalescence, which the numerical model results argue would strengthen the hurricane, but not much.
One of the biggest problems is, however, that it would take a lot of the stuff to even hope to have an impact. A C-5A heavy-lift transport airplane can carry a ton payload. So that treating the eyewall would require sorties. A typical average reflectivity in the eyewall is about 40 dB Z , which works out to 1. If you crank the reflectivity up to 43 dB Z you need to do it every hour.
If the eyewall is only 10 km thick, you can get by with sorties every hour-and-a-half at the lower reflectivity. It was hypothesized to absorb sunlight and transfer heat such as black carbon, but it has not been carried out in real life. Additionally, it would likely have negative environmental and ecological consequences, and if added in the wrong place, it could even intensify the storm.
The idea here is to spread a layer of sunlight absorbing or reflecting particles such as micro-encapsulated soot, carbon black, or tiny reflectors at high altitude around a hurricane. This would prevent solar radiation from reaching the surface and cooling it, while at the same time increase the temperature of the upper atmosphere.
Being vertically oriented, tropical cyclones are driven by energy differences between the lower and upper layer of the troposphere. Reducing this difference should reduce the forces behind hurricane winds. It would take a tremendous amount of whichever substance you choose to alter the energy balance over a wide swath of the ocean in order to have an impact on a hurricane. Knowing where to place it would also be tricky.
These proposals would require a great deal of precisely-timed, coordinated activity to spread the layer, while running the risk of doing more harm than good.
Many computer simulations should be run before any field test were tried. There has been some experimental work in trying to develop a liquid that when placed over the ocean surface would prevent evaporation from occurring.
If this worked in the tropical cyclone environment, it would probably have a limiting effect on the intensity of the storm as it needs huge amounts of oceanic evaporation to continue to maintain its intensity Simpson and Simpson However, finding a substance that would be able to stay together in the rough seas of a tropical cyclone proved to be the downfall of this idea.
There was also suggested about 20 years ago Gray et al. The idea was that one could burn a large quantity of a heavy petroleum to produce vast numbers of carbon black particles that would be released on the edges of the tropical cyclone in the boundary layer. These carbon black aerosols would produce a tremendous heat source simply by absorbing the solar radiation and transferring the heat directly to the atmosphere.
This suggestion has never been carried out in real-life. Oil slicks are patchy, and likely would not cover a big enough area to affect the hurricane. It is also difficult to predict and control how and where the oil will move when affected by the storm.
If oil happens to spill and there is a storm, the oil could be carried into or away from the coastline depending on its track, but generally the storm will have a dispersing effect. The largest impediment to this has to do with the energy expression of the hurricane. Even though a hurricane has huge amounts of energy, it is spread over a massively large area.
In essence you would need wind turbine fields dozens of miles wide could both be anchored to receive the energy and mobile to follow the storms.
Those systems would also need to withstand windblown debris and transmit the energy. There have been proposals to tow icebergs to the Atlantic and cool sea surface temperatures, or to pump deep water to the surface. The problem with this is both the size scale and the movement of the hurricane, not to mention the track uncertainty and ecological implications.
Since hurricanes draw their energy from warm ocean water, some proposals have been put forward to tow icebergs from the arctic zones to the tropics to cool the sea surface temperatures. Others have suggested pumping cold bottom water in pipes to the surface, or releasing bags of cold freshwater from near the bottom to do this.
Consider the scale of what we are talking about. The critical region in the hurricane for energy transfer would be under or near the eyewall region. If the eyewall was thirty miles 48 kilometer in diameter, that means an area of nearly square miles square kilometers.
Now add in the uncertainty in the track, which is currently miles km at 24 hours and you have to increase your cool patch by 24, sq mi 38, sq km. For the iceberg towing method you would have to increase your lead time even more and hence the uncertainty and area cooled or risk your fleet of tugboats getting caught by the storm. Just for the US mainland from Cape Hatteras to Brownsville would mean covering , sq mi , sq km of ocean floor with devices.
Lastly, consider the creatures of the sea. If you suddenly cool the surface layer of the ocean and even turn it temporarily fresh , you would alter the ecology of that area and probably kill most of the sea life contained therein. A hurricane would be devastating enough on them without our adding to the mayhem.
Seeding clouds, towing icebergs, and blowing up hurricanes with nukes all fail to appreciate the size and power of a tropical cyclone. When Andrew hit in , the eye and eyewall devastated a swath 20 miles wide.
The heat energy released there was 5, times the combined heat and electrical power generation of the Turkey Point nuclear power plant over which the eye had passed.
Attacking every tropical disturbance that comes our way is not an efficient use of time either, since only 5 out of 80 become hurricanes in a given year. The best way to minimize the damage of hurricanes is to learn to co-exist with them. Proper building codes and understanding the assumption of risk by choosing to live in a hurricane-prone area can help people evaluate their situation. Smart hurricane prep and public education, along with improved forecasting can help when a hurricane inevitably makes landfall.
In the Atlantic basin Atlantic Ocean, Gulf of Mexico, and Caribbean Sea and in the eastern and central Pacific, as required, hurricane reconnaissance is carried out by two government agencies, the U.
Navy stopped flying hurricanes in These cargo airframes have been modified to carry weather instruments to measure wind, pressure, temperature and dew point as well as drop instrumented sondes and make other observations. AOC is presently based at Linder Airfield in Lakeland, Florida and among its fleet of planes has two P-3 Orions , originally made as Navy sub hunters, but modified to include three radars as well as a suite of meteorological instruments and dropsonde capability.
Starting in AOC added to its fleet a Gulfstream IV jet that is able to make observations from much higher altitudes up to 45, feet. The USAF planes are the workhorses of the hurricane hunting effort. They are often deployed to a forward base, such as Antigua, and carry out most of the reconnaissance of developing waves and depressions.
Their mission in these situations is to look for signs of a closed circulation and any strengthening or organizing that the storm might be showing. This information is relayed by satellite to the hurricane specialists who evaluate this information along with data from other platforms.
The NOAA planes are more highly instrumented and are primarily used for scientific research on storms, but they may also be called upon for reconnaissance of mature hurricanes when they are threatening landfall, especially on U. The planes carry between six to fifteen people, both the flight crew and the weather crew.
Flight crews consist of an aircraft commander, co-pilot, flight engineer, navigator, and electrical and data technicians. The weather crew might consist of a flight meteorologist, lead project scientist, cloud physicist, radar scientist, and dropsonde quality scientist. The primary purpose of reconnaissance is to track the center of circulation, these are the co-ordinates that the National Hurricane Center issues, and to measure the maximum winds.
The purposes of research are more varied. Onboard scientists direct the aircraft to those parts of the storm of interest, which might not be near the eye of the hurricane. In certain circumstances, a USAF WC will also be assigned to fly a similar pattern in coordination with the G-IV to increase the coverage of this synoptic flow mission.
Radar and probe data are sent in real-time to be ingested into a variety of computer forecast models to ensure the best quality forecast. Sorry, but only people who are part of the mission are allowed on military and public aircraft. This may include accredited members of the press, provided they are working on a current story involving the storm. If you are an accredited reporter and want to know how to arrange for your involvement in future flights with the.
Please note that seats are not always available on every flight, and that there is a limit of two seats per media outlet on a given flight.
NOAA maintains a lengthy list of requests to fly aboard their aircraft during hurricane missions. If a hurricane is threatening landfall, local media will be given the first opportunity to fly. Due to the dynamics of hurricanes, flight plans can and do change right up until the last minute and flights are often cancelled. One might not believe this, but most hurricane flights are fairly boring. The eyewall is a donut-like ring of thunderstorms that surround the calm eye.
But what makes flying through the eyewall exhilarating and at times somewhat scary, are the turbulent updrafts and downdrafts that one hits.
Those flying in the plane definitely feel these wind currents they sometimes makes us reach for the air-sickness bags. Directly below the plane peeking through the low clouds one can see the violent ocean with waves sometimes 60 feet high [20 m] crashing into one another. Visit the page here. Read more about it in the blog post by Climate. Starting in , systematic aircraft reconnaissance was commenced for monitoring both tropical cyclones and disturbances that had the potential to develop into tropical storms and hurricanes.
This did provide much improved monitoring, but still about half of the Atlantic basin was not covered Sheets Beginning in , daily satellite imagery became available at the National Hurricane Center, and thus statistics from this time forward are most complete McAdie et al.
For hurricanes striking the USA Atlantic and Gulf coasts, one can go back further in time with relatively reliable counts of systems because enough people have lived along coastlines since Thus, the following records for the entire Atlantic Basin are divided into the pre-Satellite Era and the Satellite Era from present. How are hurricanes named? So why do people think nuking a hurricane would actually work?
Feltgen ventures that people see nuclear explosives as the ultimate tools of destruction. It was a scary time," he tells CNN. It will destroy anything. What happens if we use it against a hurricane? There's more than one way to try to stop a storm. How to prepare for a hurricane From NOAA's literature on hurricane modification efforts, it appears the nuclear option isn't the only technique people suggest. NOAA's Hurricane research division maintains a whole list debunking methods like seeding storms with silver iodide or hydroscopic particles, putting stuff on the surface of the ocean to prevent evaporation, cooling the surface of the water with icebergs and harnessing the energy of a storm to at least, you know, get something out of Mother Nature's wrath.
They could earn millions of dollars and the gratitude of everyone on the shore. Such a wide array of storm prevention proposals is a testament to people's concern and ingenuity, though not necessarily their scientific acumen. There was a time though It is predicting between 10 and 17 named storms, of which will become hurricanes, including major hurricanes.
Four named storms have formed so far this year. They were Andrea, Barry, Chantal and Dorian. US hurricane was strongest in 26 years.
Storm Barry brings flood fears in Louisiana. Image source, NOAA. Mr Trump has denied making the suggestion. What effect would nuking a hurricane have? Image source, Getty Images. Atlantic hurricane season starts early Hurricanes, typhoons and cyclones: What's the difference?
The second is whether they could cause more harm than they aim to stop. Sea surface temperature must reach at least 80 degrees Fahrenheit to birth a Category 4 or 5 storm. Computer models predict increases in the frequency of these most-intense storms , especially in the Atlantic, as the globe continues to warm. By cooling the entire Earth, the sulfates might well weaken Atlantic hurricanes, according to models by a global consortium of climate scientists convened by the National Academy of Sciences.
But the research also reveals severe risks to global climate. Gadian and his partners argue that a more regional geoengineering scheme might target hurricanes with less risk of global side effects. The idea is to infuse clouds with particles of sea salt, around which water vapor would condense to form droplets. The more droplets in a cloud, the whiter it is and the more sunlight it reflects, cooling the sea below it. Gadian and marine engineer Stephen Salter, an emeritus professor at the University of Edinburgh, have proposed that marine cloud brightening could be deployed prior to hurricane season to cool the hot spots that give rise to superstorms.
Along with Latham they envision a fleet of ships that would draw up seawater and spray stratocumulus clouds overhead with a constant mist. If the ships plied the Atlantic south of hurricane alley and started spraying in November, Gadian says, ocean currents would carry the cooled water north into the alley in time for the next hurricane season. Another approach would be to make the sea itself more reflective, rather than the clouds above it.
Bubbles whiten water, as in a boat wake or a waterfall. In the case of hurricanes, he theorizes that ships pumping microscopic bubbles into their wake along tropical storm tracks could cool the water at lower cost than ships spraying the sky—and with less risk of affecting the weather elsewhere.
Finally, it would be possible in principle to cool the sea by stirring it, mixing warm surface water into the cold depths and bringing cooler water up. Some years ago Salter imagined a way of doing this passively, using wave energy. In his scheme, an array of long vertical tubes, hanging like drainpipes from enormous floating rings, reach down into the cold water.
As waves lap over the rings, the water level inside them rises above the surrounding sea, pushing the whole column of warm water downward—and forcing cooler water up to the surface. One drawback to the scheme was that all those giant drains would drift unmoored through a stormy sea.
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