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| Outline of tropical cyclones |
The main effects of tropical cyclones include heavy rain, strong wind, large storm surges near landfall, and tornadoes. The destruction from a tropical cyclone, such as a hurricane or tropical storm, depends mainly on its intensity, its size, and its location. Tropical cyclones act to remove forest canopy as well as change the landscape near coastal areas, by moving and reshaping sand dunes and causing extensive erosion along the coast. Even well inland, heavy rainfall can lead to mudslides and landslides in mountainous areas. Their effects can be sensed over time by studying the concentration of the Oxygen-18 isotope within caves.
After the cyclone has passed, devastation often continues. Fallen trees can block roads and delay rescues, with medical supplies, or slow the repairs to electrical lines, telephone towers or water pipes, which could put other lives at risk for days or months. Standing water can cause the spread of disease, and transportation or communication infrastructure may have been destroyed, hampering clean-up and rescue efforts. Nearly two million people have died globally due to tropical cyclones. Despite their devastating effects, tropical cyclones are also beneficial, by potentially bringing rain to dry areas and moving heat from the tropics poleward. Out at sea, ships take advantage of their known characteristics by navigating through their weaker, western half.
PST hazards. PST is an acronym standing for Primary, Secondary and Tertiary. A primary hazard involves destructive winds, debris and storm surge. Secondary hazards include flooding and fires. Tertiary hazards include spikes in prices of food and other necessities, as well as long term hazards like water-borne diseases.
A mature tropical cyclone can release heat at a rate upwards of 6x1014 watts.Tropical cyclones on the open sea cause large waves, heavy rain, and high winds, disrupting international shipping and, at times, causing shipwrecks. Generally, after its passage, a tropical cyclone stirs up ocean water, lowering sea surface temperatures behind it. This cool wake can cause the region to be less favorable for a subsequent tropical cyclone. On rare occasions, tropical cyclones may actually do the opposite. 2005's Hurricane Dennis blew warm water behind it, contributing to the unprecedented intensity of Hurricane Emily, which followed it closely. Hurricanes help to maintain the global heat balance by moving warm, moist tropical air to the mid-latitudes and polar regions and also by influencing ocean heat transport. Were it not for the movement of heat poleward (through other means as well as hurricanes), the tropical regions would be unbearably hot.
Shipwrecks are common with the passage of strong tropical cyclones. Such shipwrecks can change the course of history,as well as influence art and literature. A hurricane led to a victory of the Spanish over the French for control of Fort Caroline, and ultimately the Atlantic coast of North America, in 1565. The Sea Venture was wrecked near Bermuda in 1609 which led to the colonization of Bermuda and provided the inspiration for Shakespeare's The Tempest .
Mariners have a way to safely navigate around tropical cyclones. They split tropical cyclones in two, based on their direction of motion, and maneuver to avoid the right segment of the cyclone in the Northern Hemisphere (the left segment in the Southern Hemisphere). Sailors term the right side the dangerous semicircle since the heaviest rain and strongest winds and seas were located in this half of the storm, as the cyclone's translation speed and its rotational wind are additive. The other half of the tropical cyclone is called the navigable semicirclesince weather conditions are lessened (subtractive) in this portion of the storm (but are still potentially quite hazardous). The rules of thumb for ship travel when a tropical cyclone is in their vicinity are to avoid them if at all possible and do not cross their forecast path (crossing the T). Those traveling through the dangerous semicircle are advised to keep to the true wind on the starboard bow and make as much headway as possible. Ships moving through the navigable semicircle are advised to keep the true wind on the starboard quarter while making as much headway as possible.
The most significant effects of a tropical cyclone occur when they cross coastlines, making landfall then it destroys ships and lives.
Strong winds can damage or destroy vehicles, buildings, bridges, trees, personal property and other outside objects, turning loose debris into deadly flying projectiles. In the United States, major hurricanes comprise just 21% of all land-falling tropical cyclones, but account for 83% of all damage.Tropical cyclones often knock out power to tens or hundreds of thousands of people, preventing vital communication and hampering rescue efforts. Tropical cyclones often destroy key bridges, overpasses, and roads, complicating efforts to transport food, clean water, and medicine to the areas that need it. Furthermore, the damage caused by tropical cyclones to buildings and dwellings can result in economic damage to a region, and to a diaspora of the population of the region.
The storm surge, or the increase in sea level due to the cyclone, is typically the worst effect from landfalling tropical cyclones, historically resulting in 90% of tropical cyclone deaths.The relatively quick surge in sea level can move miles/kilometers inland, flooding homes and cutting off escape routes. The storm surges and winds of hurricanes may be destructive to human-made structures, but they also stir up the waters of coastal estuaries, which are typically important fish-breeding locales.
The thunderstorm activity in a tropical cyclone produces intense rainfall, potentially resulting in flooding, mudslides, and landslides. Inland areas are particularly vulnerable to freshwater flooding, due to residents not preparing adequately.Heavy inland rainfall eventually flows into coastal estuaries, damaging marine life in coastal estuaries. The wet environment in the aftermath of a tropical cyclone, combined with the destruction of sanitation facilities and a warm tropical climate, can induce epidemics of disease which claim lives long after the storm passes. Infections of cuts and bruises can be greatly amplified by wading in sewage-polluted water. Large areas of standing water caused by flooding also contribute to mosquito-borne illnesses. Furthermore, crowded evacuees in shelters increase the risk of disease propagation.
Although cyclones take an enormous toll in lives and personal property, they may be important factors in the precipitation regimes of places they affect and bring much-needed precipitation to otherwise dry regions. Hurricanes in the eastern north Pacific often supply moisture to the Southwestern United States and parts of Mexico. people and caused $9.14 billion (2005 USD) in damage.Japan receives over half of its rainfall from typhoons. Hurricane Camille (1969) averted drought conditions and ended water deficits along much of its path, though it also killed 259
On the other hand, the occurrence of tropical cyclones can cause tremendous variability in rainfall over the areas they affect: indeed cyclones are the primary cause of the most extreme rainfall variability in the world, as observed in places such as Onslow and Port Hedland in subtropical Australia where the annual rainfall can range from practically nothing with no cyclones to over 1,000 millimetres (39 in) if cyclones are abundant.
The broad rotation of a land-falling tropical cyclone often spawns tornadoes, particularly in their right front quadrant. While these tornadoes are normally not as strong as their non-tropical counterparts, heavy damage or loss of life can still occur. Tornadoes can also be spawned as a result of eyewall mesovortices, which persist until landfall.
|Deaths per year from tropical cyclones|
During the last two centuries, tropical cyclones have been responsible for the deaths of about 1.9 million people worldwide. It is estimated that 10,000 people per year perish due to tropical cyclones. The deadliest tropical cyclone was the 1970 Bhola cyclone, which had a death toll of anywhere from 300,000 to 500,000 lives.
Before Hurricane Katrina, which combined storm-tide flooding with levee-breach (dam) flooding from Lake Ponchartrain, the average death rate for tropical cyclones in the United States had been decreasing. The main cause of storm-related fatalities had been shifting away from storm surge and towards freshwater (rain) flooding.However, the median death rate per storm had increased through 1979, with a lull during the 1980–1995 period. This was due to greater numbers of people moving to the coastal margins and into harm's way. Despite advances in warning strategies and reduction in track forecast error, this increase in fatalities is expected to continue for as long as people migrate towards the shore.
While tropical cyclones may well seriously damage settlement, total destruction encourages rebuilding. For example, the destruction wrought by Hurricane Camille on the Gulf coast spurred redevelopment, greatly increasing local property values.Research indicates that the typical hurricane strike raises real house prices by a few percent for a number of years, with a maximum effect of between 3 percent to 4 percent three years after occurrence. However, disaster response officials point out that redevelopment encourages more people to live in clearly dangerous areas subject to future deadly storms. Hurricane Katrina is the most obvious example, as it devastated the region that had been revitalized after Hurricane Camille. Many former residents and businesses do relocate to inland areas away from the threat of future hurricanes as well.
In isolated areas with small populations, tropical cyclones may cause enough casualties to contribute to the founder's effect as survivors repopulate their place. For example, around 1775, a typhoon hit Pingelap Atoll, and in combination with a subsequent famine, reduced the island's population to a low level. Several generations after the disaster, as many as 10% of Pingelapese have a genetic form of color-blindness called achromatopsia.This is due to one of the survivors of the depopulation brought on by the typhoon having a mutated gene, which the population bottleneck caused to be at a higher-than-usual level in succeeding generations.
Tropical cyclones reshape the geology near the coast by eroding sand from the beach as well as offshore, rearranging coral, and changing dune configuration onshore. Their rain water gets absorbed into stalagmites within caves, creating a record of past tropical cyclone impacts.
Waves and storm surges accompanying tropical cyclonesundersea sands, erode shell deposits, break off corals from near shore reefs in their paths, and carry all this detritus landwards in a rolling wave of material that is deposited onshore, above highest astronomical tide as a ridge of sand, shell and coral. 4–5 on the Saffir-Simpson scale) crossing northeast Australia's tropical coastline since the last significant change in sea levels (about 5,000 years ago) has 'emplaced' such ridges within the coastal landscape forming, in some places, series of ridges and a geomorphological record of highest magnitude cyclones hitting the coast over 3,000–5,000 years.For example, each severe tropical cyclone (i.e. Category
Eyewitness accounts verify ridges of this kind are formed by severe tropical cyclones and two clear examples cited are the 18 kilometres (11 mi) long, 35 metres (115 ft) wide, 3.5 metres (11 ft) high coral shingle ridge deposited on Funafuti Atoll (Central South Pacific) by Cyclone Bebe in October 1972, and the large coral shingle ridge deposited on Jaluit Atoll (Marshall Islands) by Typhoon Ophelia in January 1958. In tropical northeast Australia, an intense tropical cyclone hit in March 1918 (crossing over the town of Innisfail), at which time there were eyewitness accounts of a 4.5 metres (15 ft) to 5.1 metres (17 ft) high ridge of pumice being deposited by that cyclone's surge as it crossed the coast.).
When tropical cyclones cross land, thin layers of calcium carbonate of 'light' composition (i.e. unusual isotopic ratio of Oxygen-18 and Oxygen-16) are deposited onto stalagmites in limestone caves up to 300 kilometres (190 mi) from the cyclone's path.
As the cloud tops of tropical cyclones are high and cold, and their air is humid – their rainwater is 'lighter'. In other words, the rainfall contains significantly higher quantities of unevaporated Oxygen-18 than other tropical rainfall. The isotopically lighter rainwater soaks into the ground, percolates down into caves, and, within a couple of weeks, Oxygen-18 transfers from the water into calcium carbonate, before being deposited in thin layers or 'rings' within stalagmites. A succession of such events created within stalagmites maintain a record of cyclones tracking within a 300 kilometres (190 mi) radius of caves going back centuries, millennia, or even millions of years.
At Actun Tunichil Muknal cave in central Belize, researchers drilling stalagmites with a computer- controlled dental drill accurately identified and verified evidence of isotopically light rainfall for 11 tropical cyclones occurring over a 23-year period (1978–2001).
At the Chillagoe limestone caves in northeast Australia (130 kilometres (81 mi) inland from Cairns) researchers identified and matched evidence of isotopically light rainfall with 100 years of cyclone records, and from this have created a record of tropical cyclones from 2004 back to 1200 A.D. (an 800-year record).
Severe tropical cyclones defoliate tropical forest canopy trees, remove vines and epiphytes from the trees, break tree crown stems, and cause tree falls. The degree of damage they do along their paths, at a landscape level (i.e. > 10 kilometres (6.2 mi)), can be catastrophic yet variable and patchy. Trees will break at 42 m/s (150 km/h; 94 mph), regardless of size and type. Stripping trees and scattering forest debris also provides fuel for wildfires, such as a blaze that lasted three months in 1989 and burned 460 square miles (1,200 km2) of forest that had been stripped by Hurricane Gilbert.
Assessments of cyclone damage done to tropical rainforest landscapes in northeast Australia, have produced the following typology for describing and 'mapping' the variable impacts they have along their paths, as follows:
A storm is any disturbed state of a body especially affecting its surface, and strongly implying a wind force. It may be marked by significant disruptions and lightning, heavy precipitation, heavy freezing rain, strong winds, or wind transporting some substance through the atmosphere as in a dust storm, blizzard, sandstorm, etc.
The Saffir–Simpson hurricane wind scale (SSHWS), formerly the Saffir–Simpson hurricane scale (SSHS), classifies hurricanes – Western Hemisphere tropical cyclones – that exceed the intensities of tropical depressions and tropical storms – into five categories distinguished by the intensities of their sustained winds.
Hurricane Opal was a large and powerful Category 4 hurricane that caused severe and extensive damage along the northern Gulf Coast of the United States in October 1995. The ninth hurricane and strongest tropical cyclone of the unusually active 1995 Atlantic hurricane season, Opal developed from the interaction of a tropical wave and a low-pressure area near the Yucatán Peninsula on September 27. It then crossed the Yucatán Peninsula while still a tropical depression and intensified into a tropical storm on September 30. After entering the Gulf of Mexico and then becoming a hurricane on October 2, Opal turned northeastward and strengthened significantly. By October 4, Opal was an intense 150 mph (240 km/h), Category 4 hurricane. However, the cyclone abruptly weakened to a low-end Category 3 hurricane prior to making landfall in the Florida Panhandle near Pensacola later that day. The storm quickly weakened inland and became extratropical on October 5. The remnants of Opal persisted until dissipating over Ontario by the following day.
A storm surge, storm flood, tidal surge or storm tide is a coastal flood or tsunami-like phenomenon of rising water commonly associated with low pressure weather systems. Its severity is affected by the shallowness and orientation of the water body relative to storm path, as well as the timing of tides. Most casualties during tropical cyclones occur as the result of storm surges. It is a measure of the rise of water beyond what would be expected by the normal movement related to tides.
Hurricane David was an extremely deadly hurricane which caused massive loss of life in the Dominican Republic in August 1979, and was the most intense hurricane to make landfall in the country in recorded history. A Cape Verde hurricane that reached Category 5 hurricane status on the Saffir-Simpson Hurricane Scale, David was the fourth named tropical cyclone, second hurricane, and first major hurricane of the 1979 Atlantic hurricane season, traversing through the Leeward Islands, Greater Antilles, and East Coast of the United States during late August and early September. David was the first hurricane to affect the Lesser Antilles since Hurricane Inez in 1966. With winds of 175 mph (280 km/h), David was the only storm of Category 5 intensity to make landfall on the Dominican Republic in the 20th century and the deadliest since the 1930 Dominican Republic Hurricane, San Zenon, killing over 2,000 people in its path. In addition, David was the deadliest Dominican tropical cyclone since the 1834 Padre Ruíz hurricane, which killed over 200 people.
Tropical Storm Vamei was a Pacific tropical cyclone that formed closer to the equator than any other tropical cyclone on record. The last storm of the 2001 Pacific typhoon season, Vamei developed on December 26 at 1.4° N in the South China Sea. It strengthened quickly and made landfall along extreme southeastern Peninsular Malaysia. Vamei rapidly weakened into a remnant low over Sumatra on December 28, and the remnants eventually re-organized in the North Indian Ocean. Afterward, the storm encountered strong wind shear once again, and dissipated on January 1, 2002.
Hurricane Gordon caused minor damage in the Eastern United States. The seventh named storm and fourth hurricane of the 2000 Atlantic hurricane season, Gordon developed in the extreme western Caribbean Sea from a tropical wave on September 14. Shortly thereafter, the depression moved inland over the Yucatán Peninsula and later emerged into the Gulf of Mexico on September 15. The depression began to quickly organize, and by early on September 16, it was upgraded to Tropical Storm Gordon. After becoming a tropical storm, Gordon continued to intensify and was reclassified as a hurricane about 24 hours later; eventually, the storm peaked as an 80 mph (130 km/h) Category 1 hurricane. However, southwesterly upper-level winds caused Gordon to weaken as it approached land, and it was downgraded to a tropical storm by late on September 17. At 0300 UTC on September 18, Gordon made landfall near Cedar Key, Florida as a strong tropical storm. After moving inland, Gordon rapidly weakened and had deteriorated to tropical depression status by nine hours later. Later that day, Gordon merged with a frontal boundary while centered over Georgia.
Hurricane Danny produced 13 significant (F2+) tornadoes in the Southern United States during August 1985, the most spawned by a tropical cyclone until Hurricane Ivan in 2004. The fourth named storm and third hurricane of the season, Danny developed from a tropical wave in the northwestern Caribbean Sea on August 12. The system moved northwestward and initially remained weak. Early on August 13, it brushed Cape San Antonio, Cuba before emerging the Gulf of Mexico later that day. The system then intensified into Tropical Storm Danny on August 14. Danny deepened further and became a hurricane early on the following day, while beginning to re-curve north-northwestward. Late on August 16, Danny attained its peak intensity with winds of 90 mph (150 km/h). Shortly thereafter, the storm made landfall near Grand Chenier, Louisiana at the same intensity. Early on August 17, Danny weakened to a tropical storm and was downgraded to a tropical depression several hours later. It moved east-northeastward across the Southeastern United States, until dissipating over southeastern Virginia on August 18.
Hurricane Audrey was one of the deadliest tropical cyclones in U.S. history, killing at least 416 people in its devastation of the southwestern Louisiana coast in 1957. Along with Hurricane Alex in 2010, it was also the strongest June hurricane ever recorded in the Atlantic basin basin as measured by pressure. The rapidly developing storm struck southwestern Louisiana as an intense Category 3 hurricane, destroying coastal communities with a powerful storm surge that penetrated as far as 20 mi (32 km) inland. Audrey was the first named storm and hurricane of the 1957 hurricane season. It formed on June 24 from a tropical wave that moved into the Bay of Campeche. Situated within ideal conditions for tropical development, Audrey quickly strengthened, reaching hurricane status a day afterwards. Moving north, it continued to strengthen and accelerate as it approached the United States Gulf Coast. On June 27, the hurricane reached peak sustained winds of 125 mph (205 km/h), making it a major hurricane. At the time, Audrey had a minimum barometric pressure of 946 mbar. The hurricane made landfall with the same intensity between the mouth of the Sabine River and Cameron, Louisiana, later that day, causing unprecedented destruction across the region. Once inland, Audrey weakened and turned extratropical over West Virginia on June 29.
Hurricane Bob was the first Atlantic tropical cyclone to be officially designated using a masculine name after the discontinuation of Joint Army/Navy Phonetic Alphabet names. Bob brought moderate damage to portions of the United States Gulf Coast and areas farther inland in July 1979. The storm was the first hurricane in the Gulf of Mexico to form in the month of July since 1959, and was the fifth tropical cyclone to form during the annual hurricane season. Though the origin of Bob can be traced back to a tropical wave near the western coast of Africa in late June, Bob formed from a tropical depression in the southwestern Gulf of Mexico on July 9. Tracking in a general northward direction, favorable conditions allowed for quick strengthening. Less than a day after formation, the system reached tropical storm intensity, followed by hurricane intensity on July 11. Shortly after strengthening into a hurricane, Bob reached its peak intensity with maximum sustained winds of 75 mph (121 km/h) and a minimum barometric pressure of 986 mbar. At the same intensity, Bob made landfall west of Grand Isle, Louisiana, and rapidly weakened after moving inland. However, the resulting tropical depression persisted for several days as it paralleled the Mississippi and Ohio rivers. On July 16, the system emerged into the western Atlantic, where it was subsequently absorbed by a nearby low-pressure area.
Tropical Storm Bill was a tropical storm that affected the Gulf Coast of the United States in the summer of 2003. The second storm of the 2003 Atlantic hurricane season, Bill developed from a tropical wave on June 29 to the north of the Yucatán Peninsula. It slowly organized as it moved northward, and reached a peak of 60 miles per hour (97 km/h) shortly before making landfall in south-central Louisiana. Bill quickly weakened over land, and as it accelerated to the northeast, moisture from the storm, combined with cold air from an approaching cold front, produced an outbreak of 34 tornadoes. Bill became extratropical on July 2, and was absorbed by the cold front later that day.
Landfall is the event of a storm moving over land after being over water. More broadly, and in relation to human travel, it refers to 'the first land that is reached or seen at the end of a journey across the sea or through the air, or the fact of arriving there'.
Tropical cyclone observation has been carried out over the past couple of centuries in various ways. The passage of typhoons, hurricanes, as well as other tropical cyclones have been detected by word of mouth from sailors recently coming to port or by radio transmissions from ships at sea, from sediment deposits in near shore estuaries, to the wiping out of cities near the coastline. Since World War II, advances in technology have included using planes to survey the ocean basins, satellites to monitor the world's oceans from outer space using a variety of methods, radars to monitor their progress near the coastline, and recently the introduction of unmanned aerial vehicles to penetrate storms. Recent studies have concentrated on studying hurricane impacts lying within rocks or near shore lake sediments, which are branches of a new field known as paleotempestology. This article details the various methods employed in the creation of the hurricane database, as well as reconstructions necessary for reanalysis of past storms used in projects such as the Atlantic hurricane reanalysis.
Severe weather refers to any dangerous meteorological phenomena with the potential to cause damage, serious social disruption, or loss of human life. Types of severe weather phenomena vary, depending on the latitude, altitude, topography, and atmospheric conditions. High winds, hail, excessive precipitation, and wildfires are forms and effects of severe weather, as are thunderstorms, downbursts, tornadoes, waterspouts, tropical cyclones, and extratropical cyclones. Regional and seasonal severe weather phenomena include blizzards (snowstorms), ice storms, and duststorms.
Hurricane Humberto was a Category 1 hurricane that formed and intensified faster than any other North Atlantic tropical cyclone on record, before landfall. Developing on September 12, 2007, in the northwestern Gulf of Mexico, the tropical cyclone rapidly strengthened and struck High Island, Texas, with winds of about 90 mph (150 km/h) early on September 13. It steadily weakened after moving ashore, and on September 14, Humberto began dissipating over northwestern Georgia as it interacted with an approaching cold front.
Severe Tropical Cyclone Monica was the most intense tropical cyclone, in terms of maximum sustained winds, on record to impact Australia, tied with Cyclone Marcus in 2018. The 17th and final storm of the 2005–06 Australian region cyclone season, Monica originated from an area of low pressure off the coast of Papua New Guinea on 16 April 2006. The storm quickly developed into a Category 1 cyclone the next day, at which time it was given the name Monica. Travelling towards the west, the storm intensified into a severe tropical cyclone before making landfall in Far North Queensland, near Lockhart River, on 19 April 2006. After moving over land, convection associated with the storm quickly became disorganised.
The following is a glossary of tropical cyclone terms.
Tropical Storm Alberto was a deadly pre-season tropical cyclone that caused $125 million in damage to the Gulf Coast in late May 2018. The first storm of the 2018 Atlantic hurricane season, Alberto developed on May 25 near the Yucatán Peninsula as a subtropical cyclone. As it entered the Gulf of Mexico, Alberto intensified and transitioned into a tropical cyclone. Early on May 28, Alberto reached its peak intensity, with maximum sustained winds of 65 mph (100 km/h) and a minimum pressure of 990 mbar. Afterward, however, dry air caused Alberto to weaken before it made landfall near Laguna Beach, Florida, with winds of 45 mph (75 km/h). Alberto maintained a compact area of thunderstorms as it progressed through the central United States, entering southern Michigan as a tropical depression on May 31. That day, Alberto weakened further and dissipated over Ontario.