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Hurricanes

Hurricanes. Lynette Kampa Kiva Elementary. What is a Hurricane?. A hurricane is a powerful storm that begins over a warm ocean as a cluster of thunderstorms. This group or cluster of thunderstorms grows and gains enough strength from the heat and moisture

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Hurricanes

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  1. Hurricanes Lynette Kampa Kiva Elementary

  2. What is a Hurricane? A hurricane is a powerful storm that begins over a warm ocean as a cluster of thunderstorms. This group or cluster of thunderstorms grows and gains enough strength from the heat and moisture from the warm ocean to become a hurricane.

  3. What makes a hurricane?

  4. Hurricanes… • The winds of a hurricane swirl around a calm middle zone called the eye. The eye is surrounded by a band of tall, dark clouds called the eye wall. The eye is usually 10 to 40 miles in diameter and is free of rain and large clouds. These winds can reach nearly 200 miles per hour. Damaging winds may extend 250 miles from the eye.

  5. This is a satellite animation of Hurricane Georges, which struck the Mississippi Gulf coast in 1998.)

  6. Hurricanes… • Hurricanes are referred to by different names, depending on where they start. They are called hurricanes in North Atlantic Ocean, or the Northeast Pacific Ocean. They are known as typhoons if they occur in the Northwest Pacific Ocean and tropical cyclones when they are near Australia and in the Indian Ocean.

  7. Hurricanes, Typhoons & Tropical Cyclones… • Hurricanes occur most during the summer and early fall in the Atlantic and Northeast Pacific Oceans • Typhoons occur throughout the year in the Northwest Pacific but are most frequent in summer. • In the North Indian Ocean, tropical cyclones strike in May and November. In the South Indian Ocean, the South Pacific Ocean, and off the coast of Australia, the hurricane season runs from December to March.

  8. What causes a Hurricane?

  9. Life of a Hurricane Meteorologists have divided hurricanes into four stages: • tropical disturbance • tropical depression • tropical storm • hurricane

  10. Life of a Hurricane • Tropical disturbanceis when moist air rises and becomes cooler and forms rain clouds. The excess water changes into tiny droplets of water that form clouds. The clouds in a tropical disturbance may rise to great heights, forming thunderclouds called cumulonimbus clouds.

  11. Life of a Hurricane • Tropical depression is a low-pressure area surrounded by winds that blow in a circular pattern. This low pressure area near the ocean surface draws in warm, moist air, which feeds more thunderstorms. When the winds exceed 38 miles per hour, a tropical storm has developed. The storm clouds now have a well-defined circular shape from above.

  12. Life a Hurricane • A tropical storm has developed when the winds exceed 38 miles per hour. The storm clouds now have a well-defined circular shape. The strong winds near the surface of the ocean draw more and more heat and water vapor from the ocean. The increased warmth and moisture in the air feed the storm. The warmer this column becomes, the more the pressure at the surface falls. The falling pressure, in turn, draws more air into the storm. As more air is pulled into the storm, the winds blow harder.

  13. This is a Sea Surface Temperature Map for the northern hemisphere. The yellow, orange, and red colors shows water temperatures warm enough to sustain hurricanes (> 81 degrees).

  14. A Hurricane is Born! • A tropical storm reaches hurricane status when its winds exceed 74 miles per hour. At this point the storm reaches hurricane intensity, it has a well-developed eye at its center. Surface pressure drops to its lowest in the eye. In the eyewall, warm air spirals upward, creating the hurricane's strongest winds. The speed of the winds in the eyewall is related to the diameter of the eye.

  15. What are the effects and damage created by a Hurricane? • Hurricane damage is created from the wind and water. Hurricane winds can uproot trees and tear the roofs off houses. The fierce winds also create danger from flying debris. Heavy rains may cause flooding and mudslides. • The most dangerous effect of a hurricane, however, is a rapid rise in sea level called a storm surge. A storm surge is produced when winds drive ocean waters ashore. Storm surges are dangerous because many coastal areas are densely populated and lie only a few feet or meters above sea level. history.

  16. What happens after the Hurricane? • FEMA Helps Families Recover and Communities rebuild • In the two years since Hurricanes Katrina and Rita struck the Gulf Coast, FEMA has provided billions of dollars in assistance to help people in Louisiana, Mississippi, Texas and Alabama rebuild their lives, their homes and their communities. • FEMA has provided approximately $7.6 billion to over 1.4 million households who suffered damage or lost everything - homes, cars and all their belongings. The money was used to make 185,000 damaged homes habitable again. For homes beyond repair, the money is being used to relocate families and to replace necessary items lost in the disaster. • FEMA also has provided more than $8.3 billion in Public Assistance grants to help state and local governments rebuild schools, hospitals, roads, and government buildings and to remove debris left by the storms. Two years after, FEMA has removed of over 111 million cubic yards of debris, enough to fill 20 Superdomes.

  17. Interesting Facts about Hurricanes • There are approximately 85 hurricanes, typhoons, and tropical cyclones occur in a year throughout the world. • A 1970 cyclone in East Pakistan (now Bangladesh) produced a surge that killed about 266,000 people. A hurricane in Galveston, Texas, in 1900 produced a surge that killed about 6,000 people, the worst natural disaster in United States • Hurricanes rotate in a counter-clockwise direction around an "eye." The center of the storm or "eye" is the calmest part.

  18. Diagram of hurricane formation showing movement of warm, humid air and cold, unstable air between the upper and lower atmosphere.

  19. Review Quiz . • 1.) How are hurricanes formed? • 2.) What kind of damage can be caused by a hurricane?   • 3.) Explain when does a tropical storm becomes a hurricane?

  20. Glossary: • Hurricane - a severe tropical storm in which winds with speeds in excess of 116 km/h (73 mph) blow around an area of intensely low pressure; towering clouds bring torrential rain • Eye-The calm middle zone where winds of a hurricane swirl around • Cumulonimbus Cloud - a towering cloud that extends upward to levels of 6-7 km above the earth's surface. Strong updrafts and downdrafts are associated with this cloud generating heavy rain and often hail.

  21. Works Cited: • http://mmem.spschools.org/grade5science/weather/hurricanediagram.html • http://www.learnnc.org/lp/multimedia/2367 • http://www.nasa.gov/worldbook/hurricane_worldbook.html • http://www.teachnet-lab.org/hornik/hurricanes/hurricanediagram.htm • http://www.weatherwizkids.com/weather-hurricane.htm • http://www.fema.gov/kids/hurr.htm • http://kids.earth.nasa.gov/archive/hurricane/tour.html

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