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Hurricanes

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hurricane is a huge storm! It can be up to 600 miles across and have strong winds spiraling inward and upward at speeds of 75 to 200 mph.

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Hurricanes

  1. 1. Group Members Muhammad Nauman Zia Muhammad Ali Raza Zia Ur Rehman
  2. 2. Contents  Introduction  History of Hurricanes  Season of Hurricanes  Formation  Structure of Hurricanes  Movement of Hurricanes  Hurricane Tracking  Hurricane Forecasting  The Difference between Hurricanes, Typhoons, and Cyclones Watches and Warnings  Areas at Risk  Storm Surge  Damage Potential
  3. 3. Introduction The word Hurricane comes from the Spanish word “Hurácan” A hurricane is a huge storm! It can be up to 600 miles across and have strong winds spiraling inward and upward at speeds of 75 to 200 mph. Hurricanes gather heat and energy through contact with warm ocean waters. Hurricanes rotate in a counter-clockwise direction around an "eye" in the Northern Hemisphere and clockwise direction in the Southern Hemisphere. When they come onto land, the heavy rain, strong winds and large waves can damage buildings, trees and cars.
  4. 4. History of Hurricanes Galveston Hurricane 1900:  On September 8, 1900, a Category 4 hurricane ripped through Galveston, Texas, killing an estimated 6,000 to 8,000 people.  At the time of the 1900 hurricane, Galveston was filled with vacationers.  Sophisticated weather forecasting technology didn’t exist at the time, but the U.S. Weather Bureau issued warnings telling people to move to higher ground. However, these advisories were ignored by many vacationers and residents alike.  A 15-foot storm surge flooded the city, which was then situated at less than 9 feet above sea level, and numerous homes and buildings were destroyed.  The hurricane remains the worst weather-related disaster in U.S. history in terms of loss of life.  It had estimated winds of 145 miles per hour (233 km/h) at landfall.
  5. 5. History of Hurricanes Hurricane Katrina 2005:  Early in the morning on August 29, 2005, Hurricane Katrina struck the Gulf Coast of the United States. When the storm made landfall, it had a Category 3 rating on the Saffir-Simpson Hurricane Scale–it brought sustained winds of 100–140 miles per hour–and stretched some 400 miles across. The storm itself did a great deal of damage, but its aftermath was catastrophic. Hundreds of thousands of people in Louisiana, Mississippi and Alabama were displaced from their homes, and experts estimate that Katrina caused more than $100 billion in damage. An estimated 1,836 people died in the hurricane.
  6. 6. History of Hurricanes Hurricane Isabel 2003: On September 18, 2003, Hurricane Isabel made landfall as a Category 2 hurricane between Cape Lookout and Ocracoke Island in North Carolina with winds of 105 mph. The storm tracked northwest through North Carolina, Virginia, West Virginia, and into Pennsylvania, causing over $5 billion in damage. The storm became extra tropical over Pennsylvania and tracked into Canada.
  7. 7. History of Hurricanes Hurricane Ike 2008: On September 13, 2008, Hurricane Ike made landfall in Texas at the north end of Galveston Island, sending a 10- to 15-foot storm surge into Galveston and parts of the western end of Galveston Bay, and up to a 20-foot surge over the Bolivar Peninsula and parts of Chambers County, Texas. Virtually every structure on parts of the Bolivar Peninsula was wiped away. Broken glass littered streets in downtown Houston. Ike was responsible for $29.5 billion in damage, making it the second-costliest U.S. hurricane on record, second only to Katrina at the time.
  8. 8. Season of Hurricanes Hurricane season is a set of days corresponding to the likelihood of the development of a tropical depression, tropical storm, or hurricane. The hurricane season officially runs from June 1st through November 30th. The peak season for Maine begins the last week in August and runs through the end of September. North Atlantic Ocean:  Hurricane season: June 1 - November 30  The most active period runs from about mid August through the latter part of October.
  9. 9. Season of Hurricanes Eastern North Pacific Ocean:  Hurricane season: May 15 - November 30 This is the second most active region for tropical cyclones in the world. Northwest Pacific Ocean: Typhoon season: All year. This is the most active basin in the world. Most typhoons form between Julys through November. Bay of Bengal / Arabian Sea:  Severe Cyclonic storm season: April 1 - December 30 This basin has a double maximum because of the monsoon trough moving through at two different times of the year.
  10. 10. Season of Hurricanes Southwest Pacific Ocean:  Severe Tropical Cyclone Season: October 15 - May 1. These tropical cyclones may affect eastern Australia. Southeast Indian Ocean:  Severe Tropical Cyclone Season: October 15 - May. This basin has a double maximum in mid January, and mid February through early March. Southwest Indian Ocean: Tropical Cyclone Season: October 15 - May 15. These tropical cyclones may affect Madagascar and southeastern Africa.
  11. 11. Formation Hurricanes typically begin as a cluster of clouds and thunderstorms. These clusters of storms usually move from east to west driven by the trade winds. The birth of a hurricane requires at least three conditions. First, the ocean waters must be warm enough at the surface to put enough heat and moisture into the overlying atmosphere to provide the potential fuel for the thermodynamic engine that a hurricane becomes.
  12. 12. Formation Second, atmospheric moisture from sea water evaporation must combine with that heat and energy to form the powerful engine needed to propel a hurricane. Third, a wind pattern must be near the ocean surface to spirals air inward. Bands of thunderstorms form, allowing the air to warm further and rise higher into the atmosphere. If the winds at these higher levels are relatively light, this structure can remain intact and grow stronger: the beginnings of a hurricane!
  13. 13. Formation
  14. 14. Structure of Hurricanes A mature hurricane is nearly circular in shape. The winds of a hurricane are very light in the center of the storm (blue circle in the image below) but increase rapidly to a maximum 10-50 km (6-31 miles) from the center (red) and then fall off slowly toward the outer extent of the storm (yellow).
  15. 15. Structure of Hurricanes Three main features make up a hurricane: Eye: The eye is the "hole" at the center of the storm. Winds are light in this area. Skies are partly cloudy, and sometimes even clear. Eye wall: The eye wall is a ring of thunderstorms. These storms swirl around the eye. The wall is where winds are strongest and rain is heaviest.
  16. 16. Structure of Hurricanes Rain bands: Bands of clouds and rain go far out from a hurricane's eye wall.  These bands stretch for hundreds of miles. They contain thunderstorms and sometimes tornadoes.
  17. 17. Movement of Hurricanes The typical hurricane moves at an average speed of around 12 mph. Its movement is affected by several factors including the upper level winds called “steering currents”, and by other areas of high and low pressure. The movement of a hurricane from one location to another is known as hurricane propagation. The hurricane propagates in the direction of this wind field, which also factors into the system’s propagation speed.
  18. 18. Hurricane Tracking Tropical cyclones usually form far at sea and spend much of their existence over remote oceanic areas, detection and monitoring of these storms have traditionally posed serious problems to the forecaster. The advent of geostationary weather satellites has largely solved the detection problem and has improved the monitoring problem. However, the satellites are remote sensors and it is not unusual for position estimates to have errors of tens of miles or for wind speed estimates to be in error by tens of knots. Although advancements have been made using microwave imagery, it is still not possible to determine surface wind field distributions or detailed structural characteristics of tropical cyclones from present satellites.
  19. 19. Hurricane Tracking Hurricane Hunters: The brave "hurricane hunters" work for the National Oceanic and Atmospheric Administration (NOAA). Each mission lasts about ten hours, with the crews passing four to six times through the storm. The planes carry radar, sophisticated computers, and weather instruments that determine characteristics such as temperature, air pressure, wind speed, and wind direction inside the hurricane. The crews also release instruments that measure temperature, air pressure, and wind at different levels as the devices drop through the hurricane toward the ocean. By mission's end, NOAA can warn everyone in the hurricane's path.
  20. 20. Hurricane Tracking Satellites: The first satellite sent up by the United States to monitor weather conditions was TIROS in 1960.  Though its capabilities were primitive compared to today's satellite technology, TIROS it opened the door for meteorologists to understand a great deal more about tropical cyclones. Satellite images are very important to forecasters because by putting several hours of satellite pictures into motion, they can gather information on the track and development of the tropical cyclone.
  21. 21. Hurricane Tracking Doppler Radar: New Doppler radar can detect rain associated with tropical cyclones. It typically covers rain within a 200 to 250 mile distance from the radar location and provides estimates of rainfall amounts and depicts hurricane's rain bands, its eye and its eye wall. The newest generation of Doppler radar provides forecasters with improved data on the movement of tropical cyclones, tornado activity that can accompany a tropical cyclone, and estimates of wind speed within a tropical cyclone.
  22. 22. Hurricane Forecasting The responsibility of predicting these tracks falls on the National Hurricane Center (NHC) in Coral Gables, Florida (near Miami). One of the most useful tools forecasters have at their disposal is the use of computers. There are several computer models that are created. Some models are statistical while others are dynamic. Statistical models use the climatologically data of past hurricane movement to predict movement of the current storm. Dynamic models use equations to simulate atmospheric conditions at different levels of the atmosphere to predict a storms future movement.
  23. 23. The Difference between Hurricanes, Typhoons, and Cyclones Aside from slightly different wind speeds, there is no difference between a hurricane, a typhoon, and a cyclone. They are all different names for the same kind of intense low pressure system. Most people are familiar with two different types of weather systems:  Low pressure systems, also called "cyclones," spin counter-clockwise in the northern hemisphere  High pressure systems, also called "anticyclones," spin clockwise in the northern hemisphere. All low pressure systems are cyclones. There are two different kinds of cyclones that affect the United States most often: tropical cyclones and extra tropical cyclones
  24. 24. The Difference between Hurricanes, Typhoons, and Cyclones Tropical Cyclones: A tropical cyclone is a warm-core system that has a warm, humid, tropical air mass throughout the entire storm. Tropical cyclones derive their energy from the intense thunderstorm activity that forms around the eye of the storm. Tropical cyclones most often take on the appearance of a tight, spiraling mass of clouds...or a big white bagel. Tropical cyclones has no fronts.  Strongest winds are near the Earth's surface.
  25. 25. The Difference between Hurricanes, Typhoons, and Cyclones Extra tropical Cyclones:  From fall through the winter and well into spring, extra tropical storms dominate the weather across much of the United States and other parts of the globe outside the tropics.  "Extra tropical" means the storms originate outside the tropics.  These storms move generally west to east across the oceans and continents.  The extra tropical storm's center is an area of low atmospheric pressure with winds going counterclockwise in the Northern Hemisphere, clockwise south of the equator.  The winds pulls cold air toward the equator from the polar regions and bring warm air toward the poles.  The clash of warm and cold air leads to the widespread precipitation the storms bring.  Strongest winds in the upper atmosphere.
  26. 26. Watches and Warnings The National Weather Service is responsible for collecting data, creating forecasts, and disseminating warnings to the public. When a watch or a warning is issued, preparations should begin for the predicted weather event.
  27. 27. Watches and Warnings Watches are issued by the NOAA's SPC, and warnings are issued by local offices of the National Weather Service (NWS). Severe Thunderstorm Watch & Warning: A severe thunderstorm watch is issued whenever there is the possibility of a severe thunderstorm within a specified area.  A severe thunderstorm is defined as one with tornadoes and/or funnel clouds, hail of ¾ inch in diameter, and/or winds in excess of 58 mph.
  28. 28. Watches and Warnings Tornado Watch& Warning: A tornado watch is issued whenever the conditions are favorable for tornado development. A Tornado warning is issued when a tornado has been spotted and is issued for a specific area. Tropical Storm Watch & Watch: A Tropical Storm Watch is issued for coastal areas when there is the threat of tropical storm conditions within 36 hours. A Tropical Storm Warning is issued when tropical storm conditions, including sustained winds of 39 to 73 mph are expected within 36 hours or less.
  29. 29. Watches and Warnings Hurricane Watch & Warning: A Hurricane Watch is issued when hurricane conditions pose threat to a specified coastal area within 36 hours. A Hurricane Warning is issued when sustained winds of 74mph or higher are expected in a specified coastal area within 24 hours or less.
  30. 30. Areas at Risk COASTAL AREAS: All coastal areas of Maine are subject to hurricanes or tropical storms. The coastal areas are subject to a higher risk than inland areas due to storm surge, storm tide, higher winds, and heavy rains. In addition, coastal areas have a greater need for evacuations than do inland areas.
  31. 31. Areas at Risk INLAND AREAS:  Inland areas of Maine are also at risk of hurricanes and tropical storms.  The risk is higher for southern Maine than it is for northern parts. This is due to the fact that hurricane winds have usually been reduced substantially by the time the storm reaches northern Maine. However, the risk is still high for all inland areas for flooding.  Especially for towns located along rivers and streams such as the Androscoggin and Little Androscoggin Rivers.
  32. 32. Storm Surge A storm surge is a change in sea level that is caused by a storm. They can lead to extensive flooding and are dangerous for people living in many coastal areas. For example, when Hurricane Katrina approached the US coast in 2005, it generated a storm surge of more than 8 meters in some areas. This led to widespread flooding, including almost all of the city of New Orleans where the sea defenses couldn't cope with the water level. More than 1800 people were killed across the US by Hurricane Katrina, many of them by the storm surge flooding. The main cause of a storm surge is high winds pushing the sea water towards the coast, causing it to pile up there
  33. 33. Damage Potential Saffir—Simpson Damage Potential Scale:  In 1972, Robert Simpson, former Director of the National Hurricane Center had difficulty describing to emergency management and disaster officials what to expect for damage from approaching hurricanes.  The determination was made that a scale was needed to give disaster officials an idea of what to expect.  Herbert Saffir, a consulting engineer who was known as the “father of the Miami building code” was enlisted to work with Simpson on this project. Together they created the Saffir-Simpson Damage Potential Scale that is used today. The scale was introduced in public advisories in 1975, and is described below:
  34. 34. Damage Potential Category 1 (74-95 MPH) Damage is done primarily to shrubbery, trees, foliage, and unanchored mobile homes. No real damage to other structures, though there may be some damage to poorly constructed signs. A storm surge of 4 to 5 feet above normal is to be expected. Low-lying coastal roads will become inundated, and there would be minor pier damage.
  35. 35. Damage Potential Category 2 ( 96-110 MPH ):  Considerable damage to shrubbery, tree foliage, and vegetation can be expected, and some trees may be blown down.  Major damage is possible to exposed mobile homes, and extensive damage to poorly constructed signs.  There may also be some damage to the roofing materials, doors, and/or windows of buildings.  A storm surge of 6 to 8 feet above normal can be expected. Low-lying escape routes to inland areas can be cut off by rising water from 2 to 4 hours in advance of the storm center.  Small craft will be torn from their moorings in exposed anchorage.  Evacuation of some shoreline residences and low-lying island areas will be required.
  36. 36. Damage Potential Category 3 (111-130 MPH ): Foliage will be torn from trees and some large trees will be blown down. Practically all poorly constructed signs will be blown down. There will be some damage to roofing, doors, and windows. There may also be structural small residences and utility buildings, with a minor amount of curtain-wall failures. Mobile homes can be destroyed. A storm surge of 9 to 12 feet above normal can be expected that would cause serious flooding along the coast. Many smaller structures along the coastline may be destroyed, and larger structures may be damaged by battering waves and floating debris.
  37. 37. Damage Potential Low-lying escape routes to inland areas can be cut off by rising water from 3 to 5 hours in advance of the storm center. Flat terrain 5 feet or less above sea level will be flooded inland up to 8 miles or more. Evacuation of low-lying area residences within several blocks of the shoreline would possibly be required.
  38. 38. Damage Potential Category 4 (131-155 MPH): Shrubs, trees, and signs are blown down. There will be extensive damage to roofing materials, doors, and windows. Complete failure of roofs on many small residences, and complete destruction of mobile homes. A storm surge of 13 to 18 feet above normal can be expected.  Flat terrain 10 feet or less above sea level will be flooded as far as 6 miles. Major damage will occur to lower floors of structures near the shoreline due to flooding and battering of waves and floating debris.
  39. 39. Damage Potential Low-lying escape routes to inland areas can be cut off by rising water from 3 to 5 hours in advance of the storm center. Major erosion of beaches can be expected, and massive evacuation of all residences within 500 yards of the shoreline will possible be required. Evacuation of single story residences on low ground within 2 miles of shore will be required
  40. 40. Damage Potential Category 5 (155 MPH): Shrubs, trees, and signs will be blown down. Considerable damage to roofs and very severe damage to windows and doors can be expected. Complete failure of roofs on many small residences and industrial buildings. Extensive shattering of glass in windows and doors, as well as some complete building failures. Small buildings are overturned or blown away. Complete destruction of mobile homes. A storm surge in excess of 18 feet above normal can be expected.
  41. 41. Damage Potential Major damage to the lower floors of all structures less than 15 feet above sea level and within 500 yards of shore. Low-lying escape routes to inland areas are cut off by rising water from 3 to 5 hours in advance of the storm center. Massive evacuation of residential areas on low ground within 5 to 10 miles of shore possibly required.
  42. 42. References http://meted.ucar.edu/ of the University Corporation for Atmospheric Research (UCAR) pursuant to a Cooperative Agreements with the National Oceanic and Atmospheric Administration, U.S. Department of Commerce. http://www.aoml.noaa.gov/hrd/tcfaq/A15.html http://www.aoml.noaa.gov/hrd/tcfaq/A4.html http://www.hurricanescience.org/science/science/hurricanestructure/ http://www.nc-climate.ncsu.edu/climate/hurricanes/structure.php http://www.lakeeriewx.com/Meteo241/ResearchTopicFour/HurricaneStructure.html http://www.hurricanescience.org/science/science/hurricanemovement/ http://www.ametsoc.org/policy/hurr2.html http://thevane.gawker.com/what-is-the-difference-between-a-cyclone-typhoon-and- 1617803648 http://www.weather.com/encyclopedia/charts/tropical/saffirscale.html http://www.weather.com/outlook/weather-news/hurricanes/articles/hurricane-tracking- hurricanes_2010-05-24 Hurricanes & Tropical Storms Their Impact on Maine and Androscoggin County by Wayne Cotterly http://www.nhc.noaa.gov/outreach/history/

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