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Cyclones and hurricanes

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Nature and flora

Polar vortex

A polar vortex is an upper level low-pressure area lying near the Earth's poles. There are two polar vortices in the Earth's atmosphere, overlying the North and South Poles. Each polar vortex is a persistent, large-scale, low-pressure zone that rotates counter-clockwise at the North Pole and clockwise at the South Pole, i.e., both polar vortices rotate eastward around the poles. The bases of the two polar vortices are located in the middle and upper troposphere and extend into the stratosphere. Beneath that lies a large mass of cold, dense Arctic air.

Nature and flora

Hurricane Katrina

Hurricane Katrina was an extremely destructive and deadly Category 5 hurricane that struck the Gulf Coast of the United States in August 2005, causing catastrophic damage from central Florida to eastern Texas. Subsequent flooding, caused largely as a result of fatal engineering flaws in the flood protection system around the city of New Orleans, precipitated most of the loss of lives. The storm was the third major hurricane of the record-breaking 2005 Atlantic hurricane season, as well as the third most intense tropical cyclone on record to make landfall in the United States, behind only the 1935 Labor Day hurricane and Hurricane Camille in 1969.

Nature and flora, Science

Tropical cyclone

A tropical cyclone is a rapidly rotating storm system characterized by a low-pressure center, a closed low-level atmospheric circulation, strong winds, and a spiral arrangement of thunderstorms that produce heavy rain. Depending on its location and strength, a tropical cyclone is referred to by different names, including hurricane, typhoon, tropical storm, cyclonic storm, tropical depression, and simply cyclone. A hurricane is a tropical cyclone that occurs in the Atlantic Ocean and northeastern Pacific Ocean, and a typhoon occurs in the northwestern Pacific Ocean; while in the south Pacific or Indian Ocean, comparable storms are referred to simply as "tropical cyclones" or "severe cyclonic storms".

Nature and flora

Hurricane Irma

Hurricane Irma was an extremely powerful and catastrophic Cape Verde hurricane, the strongest observed in the Atlantic in terms of maximum sustained winds since Wilma, and the strongest storm on record to exist in the open Atlantic region. Irma was the first Category 5 hurricane to strike the Leeward Islands on record, followed by Hurricane Maria two weeks later, and is the second-costliest Caribbean hurricane on record, after Maria. The ninth named storm, fourth hurricane, second major hurricane, and first Category 5 hurricane of the 2017 Atlantic hurricane season, Irma caused widespread and catastrophic damage throughout its long lifetime, particularly in the northeastern Caribbean and the Florida Keys. It was also the most intense hurricane to strike the continental United States since Katrina in 2005, the first major hurricane to make landfall in Florida since Wilma in the same year, and the first Category 4 hurricane to strike the state since Charley in 2004.

Nature and flora

Hurricane Harvey

Hurricane Harvey of 2017 is tied with 2005's Hurricane Katrina as the costliest tropical cyclone on record, inflicting $125 billion in damage, primarily from catastrophic rainfall-triggered flooding in the Houston metropolitan area. It was the first major hurricane to make landfall in the United States since Wilma in 2005, ending a record 12-year span in which no hurricanes made landfall at the intensity of a major hurricane throughout the country. In a four-day period, many areas received more than 40 inches (1,000 mm) of rain as the system slowly meandered over eastern Texas and adjacent waters, causing unprecedented flooding. With peak accumulations of 60.58 in (1,539 mm), Harvey was the wettest tropical cyclone on record in the United States. The resulting floods inundated hundreds of thousands of homes which displaced more than 30,000 people and prompted more than 17,000 rescues.

Nature and flora

Hurricane Sandy

Hurricane Sandy was the deadliest and most destructive hurricane of the 2012 Atlantic hurricane season. Inflicting nearly $70 billion in damage, it was the second-costliest hurricane on record in the United States until surpassed by hurricanes Harvey and Maria in 2017. The eighteenth named storm, tenth hurricane, and second major hurricane of the year, Sandy was a Category 3 storm at its peak intensity when it made landfall in Cuba. While it was a Category 2 hurricane off the coast of the Northeastern United States, the storm became the largest Atlantic hurricane on record. At least 233 people were killed along the path of the storm in eight countries.

Nature and flora


A typhoon is a mature tropical cyclone that develops between 180° and 100°E in the Northern Hemisphere. This region is referred to as the Northwestern Pacific Basin, and is the most active tropical cyclone basin on Earth, accounting for almost one-third of the world's annual tropical cyclones. For organizational purposes, the northern Pacific Ocean is divided into three regions: the eastern, central, and western. The Regional Specialized Meteorological Center (RSMC) for tropical cyclone forecasts is in Japan, with other tropical cyclone warning centers for the northwest Pacific in Hawaii, the Philippines and Hong Kong. While the RSMC names each system, the main name list itself is coordinated among 18 countries that have territories threatened by typhoons each year. Only the Philippines use their own naming list for systems approaching the country.

Nature and flora

Typhoon Haiyan

Typhoon Haiyan, known as Super Typhoon Yolanda in the Philippines, was one of the strongest tropical cyclones ever recorded. On making landfall, Haiyan devastated portions of Southeast Asia, particularly the Philippines. It is the deadliest Philippine typhoon on record, killing at least 6,300 people in that country alone. In terms of JTWC-estimated 1-minute sustained winds, Haiyan is tied with Meranti for being the strongest landfalling tropical cyclone on record. In January 2014, bodies were still being found.

Nature and flora

Hurricane Andrew

Hurricane Andrew was a Category 5 Atlantic hurricane that struck the Bahamas and Florida in mid-August 1992, the most destructive hurricane to ever hit the state until Hurricane Irma surpassed it 25 years later. It was the strongest in decades and the costliest hurricane to make landfall anywhere in the United States until it was surpassed by Katrina in 2005. Andrew caused major damage in the Bahamas and Louisiana, but the greatest impact was felt in South Florida, with sustained wind speeds as high as 165 mph (270 km/h). Passing directly through the city of Homestead in Dade County, it stripped many homes of all but their concrete foundations. In total, it destroyed more than 63,500 houses, damaged more than 124,000 others, caused $27.3 billion in damage, and left 65 people dead.

Nature and flora

Hurricane Klaus

Hurricane Klaus was a minimal Atlantic hurricane that dropped heavy rainfall across the Lesser Antilles in October 1990. The eleventh tropical cyclone and sixth hurricane of the 1990 Atlantic hurricane season, Klaus developed from a tropical wave on October 3 a short distance east of Dominica. It drifted northwestward, and quickly intensified to attain hurricane status on October 5. Though its closest approach to the Lesser Antilles was within 12 miles (19 km), the strongest winds remained to its northeast due to strong wind shear, which caused Klaus to steadily weaken. After deteriorating into a tropical depression, Klaus briefly restrengthened over the Bahamas before dissipating on October 9 under the influence of developing tropical storm, Marco.

Nature and flora

Cold-core low

A cold-core low, also known as an upper level low or cold-core cyclone, is a cyclone aloft which has an associated cold pool of air residing at high altitude within the Earth's troposphere. It is a low pressure system that strengthens with height in accordance with the thermal wind relationship. If a weak surface circulation forms in response to such a feature at subtropical latitudes of the eastern north Pacific or north Indian oceans, it is called a subtropical cyclone. Cloud cover and rainfall mainly occurs with these systems during the day. Severe weather, such as tornadoes, can occur near the center of cold-core lows. Cold lows can help spawn cyclones with significant weather impacts, such as polar lows, and Von Karman Vortices. Cold lows can lead directly to the development of tropical cyclones, owing to their associated cold pool of air aloft or by acting as additional outflow channels to aid in further development.

Nature and flora

Hurricane Lili (1990)

Hurricane Lili was a moderate tropical cyclone of the 1990 Atlantic hurricane season. It began as a subtropical cyclone over the central Atlantic and became a hurricane while moving westward toward the United States. Lili did not gain any additional strength before curving away from land and weakening into a tropical storm. After transitioning into an extratropical cyclone, it made landfall in southeastern Newfoundland. Overall, the hurricane's effects on land were minimal, despite multiple tropical cyclone watches and warnings. Initial uncertainty in its track prompted some concern of a landfall in North Carolina, but it remained predominately over the open ocean.

Nature and flora

Hurricane Matthew

Hurricane Matthew was the first Category 5 Atlantic hurricane since Hurricane Felix in 2007, and also caused catastrophic damage and a humanitarian crisis in Haiti, as well as widespread devastation in the southeastern United States. The deadliest Atlantic hurricane since Hurricane Stan in 2005, Matthew was the thirteenth named storm, fifth hurricane and second major hurricane of the 2016 Atlantic hurricane season. It caused extensive damage to landmasses in the Greater Antilles, and severe damage in several islands of the Bahamas who were still recovering from Hurricane Joaquin which had pounded such areas nearly a year earlier. At one point, the hurricane even threatened to be the first storm of Category 3 or higher intensity to strike the United States since Hurricane Wilma in 2005, but Matthew stayed just offshore paralleling the Floridian coastline.

Nature and flora

Extratropical cyclone

Extratropical cyclones, sometimes called mid-latitude cyclones or wave cyclones, are low-pressure areas which, along with the anticyclones of high-pressure areas, drive the weather over much of the Earth. Extratropical cyclones are capable of producing anything from cloudiness and mild showers to heavy gales, thunderstorms, blizzards, and tornadoes. These types of cyclones are defined as large scale (synoptic) low pressure weather systems that occur in the middle latitudes of the Earth. In contrast with tropical cyclones, extratropical cyclones produce rapid changes in temperature and dew point along broad lines, called weather fronts, about the center of the cyclone.

Nature and flora

Great Storm of 1987

The Great Storm of 1987 was a violent extratropical cyclone that occurred on the night of 15–16 October, with hurricane-force winds causing casualties in England, France and the Channel Islands as a severe depression in the Bay of Biscay moved northeast. Among the most damaged areas were Greater London, the East Anglian coast, the Home Counties, the west of Brittany and the Cotentin Peninsula of Normandy which weathered gusts typically with a return period of 1 in 200 years.