HURRICANES AND TYPHOONS: PHYSICS, FORMATION AND DAMAGE

HURRICANES AND TYPHOONS

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Typhoon Soala
Hurricanes and typhoons are defined as tropical cyclones in the northern Pacific and Atlantic oceans.. Typhoons are generally in the western Pacific and generally track in a westward or northern direction, and occur most frequently in a region of the western Pacific and east Asia that includes the Philippines, Vietnam, Taiwan, southern China, South Korea, southern Japan, Guam, the Marianas Islands and parts of Micronesia. They generally do not occur south of the Philippines and blow themselves out if they travel west of Vietnam or into the interior of China. Hurricanes are generally in the western Atlantic and generally track in a westward or northern direction, and occur most frequently in a the Caribbean and southeast United States. They also occur in the Pacific where they mostly strike Mexico.

A typhoon is essentially the same thing as a hurricane, which is defined as a strong tropical storm with winds over 75 miles per hour, occurring in the west Atlantic and the eastern Pacific, particularly in southeastern North Americas and the Caribbean. Similar storms in the Indian Ocean are called tropical cyclones. Ones that strike Australia are called willie willies. Cyclone is also a catch all phrase which describes all low pressure systems over tropical waters and includes typhoons and hurricanes. All these storms feature super heavy rain as well as high winds.

The term “hurricane” has its origin in the religions of past civilizations. The Mayan storm god was named Hunraken. A god considered evil by the Taino people of the Caribbean was called Huracan. Hurricanes may not be considered evil but they are one of nature’s most powerful storms. Their potential for loss of life and destruction of property is tremendous.

The word “typhoon” comes from the Cantonese word "tai feng." The approach of a typhoon is heralded by large waves, a storm surge, and falling barometric pressure. As it gets nearer mountains of cumulus clouds appear and wind squalls intensify, climaxing with a sweeping wall of dense clouds with furious winds and torrential rain. Describing a South China Sea storm in 1935, one American captain wrote: "A terrible crash was heard! The vessel trembled like an aspen-leaf...with the sea pouring in over the bow, and the topsails shivering like so many rags." Joseph Conrad described the storms in his novels Lord Jim and Typhoon.

The typhoon and hurricane season lasts from the early summer to early autumn, but sometimes starts earlier and ends later. The early typhoon season coincided with the monsoon season in Southeast Asia and the wet season in China, Korea and Japan. The main typhoon and hurricane season is from June to November. Sometimes they appear as early as May and as late as December. Storms can be particularly fierce in years of the El Niño. Usually more damage is caused by the heavy rain than by the winds.

The highest wind ever recorded was at Mount Washington, New Hampshire in 1934: 230 miles hour

Websites and Resources

Links in this Website: LAND AND GEOGRAPHY OF JAPAN Factsanddetails.com/Japan ; CLIMATE AND WEATHER IN JAPAN Factsanddetails.com/Japan ; STORMS, FLOODS AND SNOW IN JAPAN Factsanddetails.com/Japan ; TYPHOONS Factsanddetails.com/Japan ; TYPHOONS IN JAPAN Factsanddetails.com/Japan ; NATURAL RESOURCES AND JAPAN Factsanddetails.com/Japan

Good Websites and Sources on Climate and Weather: Good Photos of the Seasons at Japan-Photo Archive japan-photo.de ; Statistical Handbook of Japan Land and Weather Chapter stat.go.jp/english/data/handbook ; 2010 Edition stat.go.jp/english/data/nenkan ; News stat.go.jp Japan Meteorological Agency Japan Meteorological Agency ; Weather Underground wunderground.com/global/JP ; Weather Channel Weather Channel ;World Climate World Climate ; Accuweather Accuweather ; Climate Data climatetemp.info/japan ;Wikipedia article on Geography of Japan Wikipedia ;

Good Websites and Sources of Storms and Floods: Weather Warnings from Japan Meteorological Agency jma.go.jp/en/warn ; Marine Warnings from Japan Meteorological Agency jma.go.jp/en/seawarn ; Wikipedia article on Snow Country in Japan Wikipedia ; Landslide Distribution Map bosai.go.jp/en ; BBC Picture Gallery of Flood in Japan news.bbc.co.uk ; Academic Paper of Flood Maps in Japan internationalfloodnetwork.org ; Tornados in Japan Survey by the American Meteorological Society ams.allenpress.com ; BBC report on 2006 Tornado bbc.co.uk

Typhoons: Typhoon and Hurricane Basics aoml.noaa.gov ; Data and Images from Pacific Typhoons eorc.jaxa.jp/ADEOS Typhoon and Hurricane Satellite Images and Photos fotosearch.com ; Video from Nasty Typhoon in Taiwan YouTube ; Typhoon Video YouTube ; Central Pacific Hurricane Center at the National Weather Service prh.noaa.gov ; Wikipedia article on Tropical Cyclones Wikipedia ; National Hurricane Center at the National Weather Service nhc.noaa.gov ; Jet Propulsion Laboratory Images of Typhoons jpl.nasa.gov/images ;

Typhoons in Japan : Typhoon and Tropical Cyclone Information from the Japan Meteorological Agency Japan Meteorological Agency ; Video of Typhoon Surfing in Japan YouTube ; Brochure on Typhoons in Japan pdf file rms.com/Publications ; Good Japan Times article on Typhoons in Japan search.japantimes.co.jp ; Digital Typhoon Information from the and United States Navy agora.ex.nii.ac.jp/digital-typhoon ; Ise-Wan Typhoon Wikipedia article on the 1959 Ise-wan Typhoon (Typhoon Vera) wikipedia.org/wiki/Typhoon_Vera ; U.S. Navy Report on the 1959 Ise-wan Typhoon pdf file usno.navy.mil and usno.navy.mil ; Lessons from the Isewan Typhoon pdf file katrina.lsu.edu/downloads/Typhoon_Isewan

Tropical Cyclones

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Typhoon Tokage
Hurricanes and typhoons are type of tropical cyclones. Tropical cyclones are warm-core, low pressure systems without any "front" attached, that develop over the tropical or subtropical waters, and have an organized circulation. Depending upon location, tropical cyclones have different names around the world. 1) In the Atlantic & Eastern Pacific Oceans they are called Hurricanes. 2) In the Western Pacific they are called Typhoons. 3) In the Indian Ocean they are called Cyclones.

Regardless of what they are called, tropical cyclones are powered by heat from the sea. They are products of a warm tropical ocean and a warm, moist atmosphere. Hurricanes are typically steered by easterly winds, generally south of 25̊ north latitude and by high-level westerly winds north of 25̊ north latitude.

Madeleine Nash wrote in Smithsonian magazine, “Hurricanes belong to a broad class of storms known as tropical cyclones, which also occur in the Indian and Pacific oceans. They do not develop spontaneously but grow out of other disturbances. In the Atlantic, most evolve out of "African waves," unstable kinks in the atmosphere that spiral off the West African coast and head toward Central America. Along the way, these atmospheric waves generate ephemeral clusters of thunderstorm-producing clouds that can seed hurricanes. At the same time, hurricanes are much more than collections of thunderstorms writ large; they stand out amid the general chaos of the atmosphere as coherent, long-lasting structures, with cloud towers that soar up to the stratosphere, ten miles above the earth's surface. The rise of warm, moist air through the chimney-like eye pumps energy into the developing storm.” [Source: Madeleine Nash, Smithsonian magazine, September 2006]

On average about 80 tropical cyclones occur annually around the world. Describing a category 5 hurricane, Madeleine Nash wrote in Smithsonian magazine, “As the storm bore down, sustained winds in the eye wall reached 160 miles per hour, with gusts that exceeded 200 miles per hour. The winds lifted up sheet metal roofs and wooden planks, hurling them through the air with lethal force; in some cases, as one writer described, "pounding sheets of sand sheared clothes and even the skin off victims, leaving them clad only in belts and shoes, often with their faces literally sandblasted beyond identification." [Source: Madeleine Nash, Smithsonian magazine, September 2006]

There are several favorable environmental conditions that must be in place before a tropical cyclone can form. They are: 1) Warm ocean waters (at least 80̊F / 27̊C) throughout a depth of about 150 ft. (46 m). 2) An atmosphere which cools fast enough with height such that it is potentially unstable to moist convection. 3) Relatively moist air near the mid-level of the troposphere (16,000 ft. / 4,900 m). 4) Generally a minimum distance of at least 300 miles (480 km) from the equator. 5) A pre-existing near-surface disturbance. 6) Low values (less than about 23 mph / 37 kph) of vertical wind shear between the surface and the upper troposphere. Vertical wind shear is the change in wind speed with height.

Although hurricanes are well known for their strong and destructive winds, a hurricane’s storm surge is by far the greatest threat to life and property along the immediate coast. Storm surge is simply water that is pushed toward the shore by the force of the winds swirling around the storm. This advancing surge combines with the normal tides to create the hurricane storm tide, which can increase the mean water level 15 feet or more. In addition, wind driven waves are superimposed on the storm tide. This rise in water level can cause severe flooding in coastal areas, particularly when the storm tide coincides with the normal high tides. Because much of the United States' densely populated Atlantic and Gulf Coast coastlines lie less than 10 feet above mean sea level, the danger from storm tides is tremendous.

Norwegian Cyclone Model

The Norwegian cyclone model, so named to honor the Norwegian meteorologists who first conceptualized the typical life cycle of cyclones in the 1910s and 1920s, presents the evolution of a cyclone. In this model, there will initially be a boundary, or front, separating warm air to the south from cold air to the north. The front is often stationary.

A wave on the front will form as an upper level disturbance embedded in the jet stream moves over the front. The front develops a "kink" where the wave is developing. Precipitation will begin to develop with the heaviest occurrence along the front.

As the wave intensifies, both cold and warm fronts become better organized. The wave becomes a mature low pressure system, while the cold front, moving faster than the warm front, "catches up" with the warm front. As the cold front overtakes the warm front, an occluded front forms.

As the cold front continues advancing on the warm front, the occlusion increases and eventually cuts off the supply of warm moist air, causing the low pressure system to gradually dissipate.

Hurricane and Typhoon Components

Amber Angelle wrote in Discover magazine: "Huge cloud columns called hot towers may develop in the eyewall and in the bands of rain swirling outward from it. These towers release tremendous amounts of heat, giving the hurricane an energy boost. Three-dimensional images of hurricane Katrina from the Tropical Rainfall Measuring Mission satellite captured nine-mile-tall hot towers emerging before the storm intensified to a category 5. A NASA analysis indicates that a hurricane is twice as likely to get stronger in the next six hours when such hot towers form. [Source: Amber Angelle, Discover, October 2010]

"Even as the outer winds reach speeds of 150 miles per hour, the eye remains remarkably calm, with winds near zero mph. But NASA found that the eye is not as benign as it appears. A combination of computer simulations and observational data reveal that air pockets from the eye can transport heat and moisture into the surrounding storm, increasing the hurricane’s intensity.

"Surrounding the eye is the eyewall, a hoop of heavy rain and violent winds. This past June scientists at NASA’s Stennis Space Center in Mississippi reported that the eyewall’s extreme conditions can stir up ocean currents 300 feet below the surface, disrupting sediment and organisms on the seafloor for as long as a week after the storm subsides. A major hurricane could even threaten undersea oil pipelines.

Hurricane and Typhoon Physics

Hurricanes and typhoons in the northern hemisphere have an eye and thunderstorm-producing cumulus clouds that spiral out in a clockwise direction from the eye. They eye is 5 to 25 miles wide and is relatively calm, sometimes windless. Strong winds blowing towards the center of the area of extreme low pressure and cirrus streamer clouds radiating in a east or southeast direction are bent by the Coriolis affect. The most destructive part of the storm is usually the northern, leading side of the storm. The east side of a typhoon generally is more devastating than the west side.

The “eyewall,” an area just beyond the eye, is the region of the storm with the most intense winds. It is often only a kilometer or so wide but it interacts with the rings of thunderstorms that produce the heaviest winds and rains and its behavior and dynamics are crucial to the behavior of the storm as a whole. The eyewall is shaped by two opposing forces: 1) moist, warm air from inside the eye, which can feed the eyewall, strengthening it; and 2) dry air from outside the eye that can slowly bleed into it, and calm it down.

Air flowing from high pressure to low pressure causes winds. If the difference between high pressure and low pressure is great, intense circulation is generated, causing a powerful storm. As air spirals into a low-pressure zone warm humid air and warm sea surface winds meet and ascend, causing clouds to billow upwards. Further lowering of air pressure can cause winds to swirl even faster towards the center.

The deflecting action of the Earth’s rotation spins the developing cyclone (counterclockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere). When water in the ascending clouds cools and falls as rain heat energy is produced, which further warms the storm, lowering the pressure and making the storm stronger. The cyclone can continue to strengthen as long as it remains over warm water and is not destroyed by vertical wind shear---winds traveling at different speeds at lower and high altitudes---which can cut off the top of a storm breaking up its energy producing engine.

Madeleine Nash wrote in Smithsonian magazine, “Ocean warmth is essential---hurricanes do not readily form over waters cooler than about 79 degrees Fahrenheit---but the right temperature is not enough. Atmospheric conditions, such as dry air wafting off the Sahara, can cause hurricanes---along with their weaker cousins, tropical storms and depressions---to falter, weaken and die. Vertical wind shear---the difference between wind speed and direction near the ocean's surface and at 40,000 feet---is another formidable foe. [Source: Madeleine Nash, Smithsonian magazine, September 2006]

Storms can change very quickly. In 2005 Hurricane Wilma jumped to a Category 5 storm in less than 24 hours. 1935 Labor Day Hurricane in the Florida Keys, Madeleine Nash wrote in Smithsonian magazine, “exploded from a Category 1 to a Category 5 hurricane in 40 hours, about the amount of time an evacuation of the Keys might take today. As the storm bore down, sustained winds in the eye wall reached 160 miles per hour, with gusts that exceeded 200 miles per hour. The winds lifted up sheet metal roofs and wooden planks, hurling them through the air with lethal force; in some cases, as one writer described, "pounding sheets of sand sheared clothes and even the skin off victims, leaving them clad only in belts and shoes, often with their faces literally sandblasted beyond identification." [Source: Madeleine Nash, Smithsonian magazine, September 2006]

Levels, Names and and Types of Hurricanes and Typhoons

Atlantic storms and hurricanes are defined as: 1) a tropical depression; 2) a tropical storm (less than 74 miles per hour); 3) Category One (between 74 and 95 miles per hour); 4) Category Two (between 95 and 110 miles per hour); 3) Category Three (between 111 and 130 miles per hour); Category Four (between 131 and 155 miles per hour); and Category Five (more than 155 miles per hour).

In Asia, different countries have different systems for identifying typhoons. Some countries such as Japan use numbers. Others use names. The most powerful storms are called Supertyphoons.

Supertyphoons and Category Five hurricanes are very destructive. They are defined as typhoons with winds over 150 miles per hour. Such storms produce horizontal rain and can measure several hundred miles across, cover thousands of square miles and reach an altitude of almost ten miles. The largest storm on record, the 1979 typhoon Tip, produced gale force across a 650 mile area.

Since 1950 American forecasters have identified storms using an alphabetical system of names. Beginning in 1953 those names were only female ones, but in 1979, at the urging of women's groups, male names were added. These days meteorologists plan ahead, compiling six years' worth of names--three male and three female for each letter of the alphabet except Q, U, X, Y, and Z (leaving 21 letters usable for names). Every six years the lists of names repeat, with the names of particularly devastating storms removed from the list. With the number of storms increasing some worry that the day will come soon when the number of storms in a given year will exceed the number of letters available for names. [Source: Whitney Dangerfield, National Geographic, Geographica. October 2005]

In the Pacific ocean a hurricane is a tropical cyclone on the east side of the international date line and a typhoon is such a storm on the west side. In recent years an increasing number of hurricanes have been crossing the international date line in the Pacific Ocean and turning into typhoons. Typhoon No. 12, for example, which struck Japan in September 2006, began on the east side of the international date line and turned into a hurricane there and crossed to the west side, when it was a category 5 storm with 270 kph winds, to became a typhoon. Typhoon no. 12 was the 16th hurricane to become a typhoon since the Japan Meteorological Agency began its monitoring operation in 1951. Before 1990 there were only six cases of this happening---two in the 1950s, one each in the 1960s and 70s, and two in the 1980s. In the 1990s there were seven such hurricanes that became typhoons and three between 2000 and 2006. [Source: Yomiuri Shimbun, September 2006]

Typhoon and Hurricane Formation

A number of things have to come together for a typhoon or hurricane to form. Among them are the presence of an initial low-pressure system that pulls the air to a particular spot in the ocean; the Coriolis effect spinning the air in a vortex; difference in wind speed in the upper and lower parts of the atmosphere that create horizontal “shear forces”; and the presence of cold air 10 miles up in the atmosphere.

Factors that influence typhoon development include water temperatures and rainfall amounts in the Pacific; El Niño (which produces high-level winds that blow the top of typhoon clouds); and stratospheric jet-streams wind patterns. Scientist also believe that typhoons can be influenced by seemingly unrelated things like the atmospheric temperatures above Singapore.

According to a study by scientists at the University College London high sea temperatures are the most reliable indicator of increased typhoon and hurricane activity. The reasoning is that warmer seas cause more water to evaporate. As the water rises, latent heat is released which provides the energy for low pressure cell to develop into a hurricane.

Typhoon Formation

Typhoons develop in an area of the tropical Pacific at a latitude between 10 and 20 degrees north. They usually begin as westward-drifting “waves” of clouds drawn into an area of low pressure around the Caroline Islands of Micronesia (between Hawaii and the Philippines in the Pacific) and grow into westward-moving tropical depressions.

As the clouds advance across the warm water they pick up energy as the water evaporates. At a critical point the clouds develop into a vortex of air that rotates in a counter-clockwise direction because of the Coriolis effect (see above). The water temperatures generally have to be above 80̊F for all this to occur. The warmer the sea surface temperature are, and the more warm, moist air there is, the stronger the storm will be.

Many so called “storm seeds” with the potential to become typhoons form in the summer west of the International Date Line in an area of the tropical Pacific at a latitude between 10 and 20 degrees north. They usually begin as westward-drifting “waves” of clouds drawn into an area of low pressure around the Caroline Islands of Micronesia (between Hawaii and the Philippines in the Pacific) and grow into westward-moving tropical depressions.

Because the Caroline Islands of Micronesia are breeding grounds for typhoons they rarely get hit by fully developed storms. Typhoons usually pass north of Palau. As the clouds advance across the warm water they pick up energy as the water evaporates. At a critical point the clouds develop into a vortex of air that rotates in a counter-clockwise direction because of the Coriolis effect (see above). The water temperatures generally have to be above 80̊F for all this to occur. The warmer the sea surface temperatures are, and the more warm, moist air there is, the stronger the storm will be.

Birth of Hurricane Katrina

Marc Kaufman wrote in the Washington Post: “Twenty-one days before Hurricane Katrina made landfall at New Orleans last summer, a relatively small "wave" of turbulent air emerged from western Africa and headed out to sea. Over the ocean, that trough of low atmospheric pressure began to shrink, and it was further diminished by a mass of dry and dusty air from a large Saharan dust storm that blew offshore at about the same time. Over the eastern and central Atlantic, the dusty cloud mingled with the tropical wave and helped keep it weak and diffuse. But somewhere out over the Atlantic, that same atmospheric wave joined up with one or more other tropical depressions coming off Africa. Within days, the relatively small turbulence grew into the tropical cyclone that, as it crossed the ocean, became the hurricane that would devastate the Gulf Coast two weeks later. [Source: Marc Kaufman, Washington Post, August 7, 2006]

“Although many hurricanes that reach the United States are born as tropical depressions in the waters off Africa, little is known about why some peter out and others become monster hurricanes on the other side of the ocean. This is increasingly important information to have, and so a team of researchers from NASA and the National Oceanic and Atmospheric Administration will spend the next two months off the African coast trying to find the answer. "These waves are pretty innocuous -- lines of heavy rain with some thunderstorms," said Jeffrey Halverson, a NASA mission scientist and professor at the University of Maryland in Baltimore County. "But about 10 percent change character as they move to sea and get rotations and start building up power. That's the big mystery: Where does the spin come from?" [Ibid]

“About 60 waves every year come off West Africa in the late summer and head toward the Caribbean and North America, carried by trade winds. Most of the time, these weather patterns -- called African easterly waves because they form over the Darfur region of Sudan or Ethiopia in East Africa -- stretch 1,200 to 1,500 miles and last three to four days before they dissipate, unless they grow into something bigger. They get their initial power and instability from the difference in temperature between the very hot Sahara Desert air and the substantially cooler air along the coast of the Gulf of Guinea. [Ibid]

Playing an important role is “the Saharan air layer that forms over the desert during the late spring, summer and early fall, and generally moves out over the tropical Atlantic Ocean. Its very hot and dry air, strong winds and airborne dust are thought to inhibit cyclone development. There is some evidence that the dust makes it more difficult for rain to form, but that factor is currently not considered in hurricane computer models. [Ibid]

20080317-typhoon_big saomi national geographic.jpg
Damage from Typhoon Saomi in August 2006

Hurricanes and Typhoon Power and Dynamics

The power generated by a major hurricane or typhoon is said to be equal to half a million nuclear bombs. The power of an average storm is said to be equal to 1.5 trillion watts---the equivalent to about half the world’s entire electrical generating capacity.

Factors that influence hurricane and typhoon development include water temperatures and rainfall amounts in the Pacific; El Niño (which produces high-level winds that blow the top off hurricane and typhoon clouds); and stratospheric jet-stream wind patterns. Scientist also believe that typhoons can be influenced by seemingly unrelated things like the atmospheric temperatures above Singapore.

According to a study by scientists at the University College London high sea temperatures are the most reliable indicator of increased typhoon and hurricane activity. The reasoning is that warmer seas cause more water to evaporate. As the water rises, latent heat is released which provides the energy for a low pressure cell to develop into a hurricane.

Hurricanes and Typhoon Engine

Hurricanes and typhoons are self-feeding and self-reinforcing events fueled by: 1) evaporated water that releases energy when it condenses back into water; and 2) driving rapid updrafts that cause water to evaporate from the ocean, forming self-sustaining vortexes of swirling clouds and high winds. The dynamics of all this---especially of forces than can cause a storm to suddenly intensify---remain little understood. Among the clues that a storm is about to intensify are the presence of chimney clouds called hot towers that can reach as high as 11 milies into the atmosphere.

Rapidly moving air over warm water absorbs unusually large amount of water vapor through evaporation. As the air converge at the center of the storm, it rises. As the air rises, it cools and some of the water vapor condenses into droplets. That process release energy in the form of “heat cf condensation.” [Source: Washington Post, ✳]

The heat is released into a column of air that is already warmer than the air outside the storm. There can be as much as a 30̊F difference between air in the eyewall and air at the same altitude outside the storm. The heat dissipates slowly, in part because the air is contained in a rotating system. Meanwhile, the newly released reheated air continues to rise, eventually losing more moisture and condensation and releasing more heat. In this way a large and powerful hurricane or typhoon can influence its environment in such a way as to allow the storm to get even bigger and stronger.✳

When the rising air exits from the system, sometimes as high as 50,000 feet above the sea surface, it is cold and relatively dry. As it departs more air is pulled in at the bottom of the storm, continuing the cycle. The energy from the warm water beneath the storm is vital to keeping the whole thing going. When a hurricane or typhoon goes over cool water or land it tends to fall apart. High upper atmosphere winds are also great typhoon killers. They can sometimes sheer the tops off of a hurricane or typhoon and cause it to suddenly collapse.

Hurricanes maintain and gain strength over the sea and lose strength when the go overland. Islands are often so small they little effect. The intensity of a storm is also related to its interaction with the sea. Warm water at the top of the ocean provides fuel. As the storm spins, it churns the water beneath it, bringing cooler water from the depths. The cooler water acts as a brake to slow the engine down. Some of the most intense storms are feed by warm water that is hundreds of meters deep and the breaking action of cooler water does not occur. Large waves can also slow a storm down by blunting the winds that created them.

Damage from Hurricanes and Typhoons

Hurricanes and typhoons can cause millions or even billions of dollars in damage. Buildings slide down hillsides; valleys flood; villages disappear under landslides and mud slides; roads and bridges are washed away; crops become waterlogged, or are blown over or uprooted, or covered in mud. Destruction levels can be particularly high when a storm stalls and strong, driving rains persist for hours or even days, or when the storm slams into mountains, producing particularly large amounts of rain. Some typhoons are so powerful they blow plankton and small sea creatures into the sky, where they float around on clouds.

Usually much more damage and death is caused by rains than winds. People die from being hit by flying debris or falling trees or crushed in collapsed building but are more likely to die from drowning in flooded rivers or from suffocating under rain-induced mud slides and landslides. Most victims from really deadly storms die from storm surges---masses of ocean water that are pushed forward by the winds---that can penetrate several miles inland. The surges are particularly deadly if they occur at high tide.

Hurricanes and typhoons often do the most damage on low coral islands which are sometimes inundated with waves that can reach a height of 30 meters at sea and storm surges that sweep water across the entire island, annihilating every tree and hut in their path. Modern buildings and houses with cinder block walls and metal roofs are usually strong enough to withstand the winds of strong typhoons but thatched-roof huts and shanties are easily blown over or crushed by falling trees. Palm trees also blow over pretty easily because they don't have a deep root system.

Long term damage and hardships from typhoons are caused by sickness and starvation as water supplies become contaminated; cholera and dysentery; poisonous snakes flooded out of their dens; damaged crops and stored food; and the disruption or destruction of transportation routes used to bring in relief supplies. Over the longer term fields and agricultural land may be is destroyed and rivers may be rerouted. Where factories are washed away and infrastructure is damaged, people may begin migrating out. In poor countries there is inevitably not enough money to fix everything.

The danger from typhoons increases with time as coastal areas become more developed and urban areas sink as result of the drawing of underground water. Global warming is predicted to raise sea levels, making the situation even more dire.

There are examples of typhoons and hurricanes striking certain areas and dramatically altering the coastline. Barrier island are particularly vulnerable, there are cases of such island that were formed thousands if years ago that have been whittled down to islets and remnants in 150 years by storms, subsiding land and rising sea levels.

Disastrous Storms

World's Worst Recorded 20th Century Cyclones, Hurricanes, Typhoons and Other Storms (number of dead): 1) Bangladesh, Nov. 13, 1970 (300,000); 2) Bangladesh, Apr. 30, 1991 (139,000); 3) H. Bengal, India, Oct. 15-16, 1942 (40,000); 4) Bangladesh, June 1-2, 1965 (30,000); 5) Bangladesh, May 28-29, 1963 (22,000); 6) Bangladesh, May 11-12, (17,000); 7) Hong Kong, Sept. 18, 1906 (10,000); 8) Bangladesh, Dec. 15, 1965 (10,000); 9) Bangladesh, May 25, 1985 (10,000); 10) Caribbean, Hurricane Flora, Oct 4-8, 1963 (6,000); hurricane in Galveston, TX, Aug-Sept, 1900 (6,000).

Hurricanes account for nine of the 10 costliest U.S. natural disasters since 1989, with Hurricane Katrina at the top of the list with $125 billion in damage and 1,833 deaths, according to the U.S. Federal Emergency Management Agency and the National Oceanic and Atmospheric Administration.

Coastal Changes Caused by Hurricanes and Typhoons

Describing changes to the northern Gulf coast caused by hurricanes there, Cain Burdeau of Associated Press wrote: “Everywhere scientists look, they see disrupted patterns in and along the Gulf of Mexico. Coral reefs, flocks of sea birds, crab- and shrimp-filled meadows and dune-crowned beaches were wrapped up in -- and altered by -- the force of hurricanes Katrina, Rita, and Dennis. ''Nothing's been like this," said Abby Sallenger, a US Geological Survey oceanographer, during a recent flight over the northern Gulf Coast to study shoreline changes. [Source: Cain Burdeau, Associated Press, February 5, 2006]

For him, the changes are mind-boggling: Some barrier islands are nearly gone; on others, beaches are scattered like bags of dropped flour. Hurricanes have been kneading the Gulf Coast like putty for eons, carving out inlets and bays, creating beaches and altering plant and animal life -- but up to now, the natural world has largely been able to rebound. Trees, marine life ,and shoreline features tourists and anglers enjoyed in recent years were largely the same types as those 17th century buccaneers and explorers encountered.

But scientists say the future could be different. Nature might not be able to rebound so quickly. The reason: the human factor. ''Natural systems are resilient and bounce back," said Susan Cutter, a geographer with the University of South Carolina. ''The problem is when we try to control nature, rather than letting her do what she does." The seas are rising, the planet is getting hotter ,and commercial and residential development is snowballing. Add those factors to a predicted increase in nasty hurricanes and what results is a recipe for potentially serious natural degradation, some say.

Surveys of the washed out Chandeleur Islands, an arc of barrier islands off the coast of Louisiana, found nesting grounds for brown pelicans, royal terns, sandwich terns, and black skimmers gone.''Hopefully the birds will be resilient enough to move to other areas," said Tom Hess, a biologist with the Louisiana Department of Wildlife and Fisheries. ''We will have to see." Salt water spread by Hurricanes Katrina and Rita killed marsh grasses across the Louisiana coast, leaving little left to eat for Louisiana's most hunted bird -- the duck. ''Most of the marsh where that salt water sat for a long time looks dead. It looks like it is does extremely late in the winter and you've had several extreme frosts," said Robert Helm, a state waterfowl biologist. ''Where we found birds, they seemed to be concentrated in the habitat that was not impacted by the storm."

A lot of things are happening under the water, too. With their towering waves, hurricanes move huge volumes of mud and sediment on the ocean bottom, burying clam and oyster beds and seagrass meadows where crabs, shrimps and fish hide and feed. Can the sea plants spring back? ''It depends on the light penetration, how deep they are buried, and factors like that," said John Dindo, a marine scientist and assistant director of the Dauphin Island Sea Lab in Alabama.

Farther out, where the continental shelf drops off, the wild seas kicked up by the hurricanes damaged the Gulf's coral reefs.After Rita's 30-plus-foot waves, surveys of the coral at the Flower Garden Banks National Marine Sanctuary 100 miles off the coast of Louisiana and Texas showed damage to about 5 percent of the reef. Brain and star coral was toppled and smashed into other coral heads. About 3 feet of sand was dispersed on sand flats in the reef where trigger fish and queen conch burrow and nest.

Improving Coastal Defenses Against Hurricanes and Typhoons

Deborah Zabarenko of Reuters wrote: “Global warming is expected to cause more severe hurricanes, and that means U.S. communities will need new tactics to minimize storm damage, emergency preparedness have experts said. These tactics range from restoring wetlands -- which may actually slow down approaching storms -- to making homes and other structures better able to withstand hurricanes to organizing finances so more can be spent on prevention, the panel of experts said. [Source: Deborah Zabarenko, Reuters, August 27, 2007]

Wetlands, which used to be drained as a matter of course in the United States, provide flood control by absorbing excess water during storms, filter pollutants before they enter streams, lakes and oceans and protect coastal areas from erosion, according to a 2006 Government Accountability Office report.

Impact of Hurricanes on Wildlife

Darryl Fears wrote in the Washington Post, “Biologists who study birds couldn’t believe what they were seeing at their research lab in Williamsburg. Two pigeon-size shorebirds they tracked with tiny satellite transmitters were doing something no one had ever recorded. They were flying through 115-mph winds of a massive hurricane.” “We were holding our breath,” Fletcher Smith, a research biologist at the Center for Conservation Biology, told the Post about the birds as they approached Hurricane Irene. “We really didn’t have a good idea of what birds are able to navigate through.” [Source: Darryl Fears, Washington Post October 2, 2011]

At the Cape Romain National Wildlife Refuge on a barrier island north of Charleston, S.C., 200 sea-turtle nests with large clutches of eggs were wiped out. Swaths of the island were washed away, which might hamper turtles from nesting next year, said Sarah Dawsey, manager of the refuge. Hurricanes pose a significant threat to endangered species whose populations have been reduced by humans, biologists said. When asked how animals in the region fared in the one-two punch of storms, they said they didn’t have much data to draw from. They based their answers on observations from past storms.

Bears move to high ground and hunker down, said one biologist. Deer plop next to fallen trees and hug them close, said another. Squirrels, opossums and raccoons slip into holes in tree stumps and logs to wait it out. Small birds squat in thick bushes. Smith said the center also put satellite transmitters on bald eagles and discovered that they, too, have a preferred method of riding out deadly storms. “They’ll just sit on a tree branch and hold on for dear life,” he said. “Most birds ride out storms that way. When they grip something, it’s easier to stay gripped than it is to let go.”

Those tactics don’t always help. More than 20 percent of bald-eagle nests along the James River were destroyed, and an additional 23 percent were damaged, according to the Center for Conservation Biology of Virginia Commonwealth University and the College of William and Mary.

“Although nine out of 10 animals can weather storms through precaution, some don’t make it,” said Judy Wink, executive director of the Chesapeake Bay Environmental Center, a wildlife refuge in Grasonville, Md. Some animals, like some people, wait too long to safely flee, Wink said. “Birds . . . if they’re late in seeking cover, they get blown into windows and porches,” she said. “Osprey babies get blown out of nests. We’ve had ospreys that were blown into power lines.”

Animals can benefit, however, when hurricanes rearrange land, biologists said. Fallen trees provide new homes. Floods create new habitats that provide sanctuary and food for turtles and frogs. Cleared fields allow for new growth, a good thing if the plants aren’t invasive and destructive, said John Kostyack, vice president of wildlife conservation for the National Wildlife Federation. “The important thing is animals do sense a storm ahead of time; they have forewarning,” Wink said. “Those who sense a change in weather and act fast have a better chance of survival.”

The flight of the whimbrels---oatmeal-colored birds with long, curved beaks---was a major breakthrough, at least with regard to birds. The center tracked four whimbrels it tagged in 2009 and 2010 to study their extraordinary flights from Virginia to breeding grounds as far away as Alaska. The birds were in the middle of migrations that started in Canada when Irene formed in the Caribbean. Migrating birds are widely believed to tire and perish when they encounter hurricanes in open waters. But as biologists followed the satellite signals, they realized that a whimbrel they named Chinquapin powered through the storm, crossing it near the Bahamas on Aug. 25. A second whimbrel they named Goshen flew through an outer band of Irene that same day, about 100 miles behind Chinquapin.

Image Sources: Typhoon News weblog

Text Sources: New York Times, Washington Post, Los Angeles Times, Daily Yomiuri, Times of London, Japan National Tourist Organization (JNTO), National Geographic, The New Yorker, Time, Newsweek, Reuters, AP, Lonely Planet Guides, Compton’s Encyclopedia and various books and other publications.

Last updated August 2020

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