Hurricanes, Typhoons & Cyclones

1. Hurricanes, Typhoons & Cyclones

2. Hurricanes, Typhoons & Cyclones Hurricanes, typhoons and cyclones are the greatest storms on Earth Their winds can exceed 185 miles (300 kilometers) per hour for long periods of time Wind gust can exceed 200 miles per hour

3. Hurricanes, Typhoons & Cyclones Hurricanes, typhoons and cyclones are simply regional names for the same type of storm Hurricanes occur in the Atlantic Ocean and the eastern Pacific Ocean Typhoons occur in the northern hemisphere in the western-north Pacific Ocean Cyclones occur in the southern hemisphere in the Indian Ocean and around Australia

4. Hurricanes, Typhoons & Cyclones Storm track of all hurricanes, typhoons and cyclones from 1985 to 2005

5. How to Create a Hurricane The Atlantic hurricane season is from June 1 to November 1

6. How to Create a Hurricane There are 6 major factors that help generate a hurricane: Temperature Rapid cooling High humidity Low wind shear Location, location, location Disturbed weather

7. How to Create a Hurricane In most situations, water temperatures of at least 26.5 °C (79.7 °F) are needed down to a depth of at least 50 meters (160 ft) Waters of this temperature cause the overlying atmosphere to be unstable enough to sustain convection and thunderstorms

8. How to Create a Hurricane An important factor is rapid cooling with height, which allows the release of the heat of condensation that powers a tropical cyclone The heat of condensation is the energy required to transform a given quantity of a substance (water) into a gas (water vapor)

9. How to Create a Hurricane Hurricanes form when the energy released by the condensation of moisture in rising air causes a positive feedback loop over warm ocean waters

10. How to Create a Hurricane High humidity is needed, especially in the lower-to-mid troposphere of the atmosphere When there is a significant amount of moisture in the atmosphere, conditions are more favorable for disturbances to develop

11. How to Create a Hurricane Low amounts of wind shear are needed, as high shear is disruptive to the storm's circulation Wind shear is a difference in wind speed and direction over a relatively short distance in the atmosphere Red indicates areas with very low wind shear

12. How to Create a Hurricane Tropical cyclones generally need to form more than 555 kilometers (345 miles) or 5 degrees of latitude away from the equator, allowing the Coriolis effect to deflect winds blowing towards the low pressure center and creating a circulation

13. How to Create a Hurricane Because the Earth rotates, the Coriolis effect causes winds and water currents to flow to the west near the equator This effect is responsible for the rotation of large tropical storms (hurricanes, typhoons & cyclones)

14. How to Create a Hurricane A formative hurricane needs a pre-existing system of disturbed weather Simply put, a tropical depression becomes a tropical storm and finally a hurricane

15. How to Create a Hurricane The current environment, geology and geography of Africa, the Atlantic Ocean, the Caribbean and the Gulf of Mexico are perfect for creating dangerous hurricanes

16. How to Create a Hurricane European seafarers have known since the 14th century that great dust storms blew off of Africa Charles Darwin even referred to these dust storms in his book, “Voyage of the Beagle”

17. How to Create a Hurricane During the summer and early fall, hot, dry atmospheric depressions (called troughs) blow to the west off of the Sahara and become tropical depressions over the Atlantic Ocean

18. How to Create a Hurricane Evaporation of the warm ocean water can rapidly add humidity to these tropical depressions The heat and humidity turns these atmospheric disturbances into rain and thunder storms (In fact, far more rain normally falls over the tropical oceans than on land)

19. How to Create a Hurricane Tropical depression have maximum sustained winds less than 35 knots (39 miles per hour) and resemble a series of disorganized thunder storms

20. How to Create a Hurricane Once a tropical depression has intensified to the point where its maximum sustained winds are between 35-64 knots (39-73 miles per hour), it becomes a tropical storm

21. How to Create a Hurricane Tropical storms are assigned a name, which they keep if they become a hurricane Compared to tropical depressions, tropical storms are more organized and more circular in shape

22. How to Create a Hurricane Finally, when the minimum sustained winds of a tropical storm exceeds 64 knots (73 miles per hour), it becomes a hurricane

23. Hurricane After ravaging North America, the remnant of a hurricane can cross the Atlantic Ocean and bring dangerous winds, high surf and heavy rains to Europe and even into Russia

24. Pacific Hurricane Many hurricanes that form in the Atlantic Ocean blow across Mexico and Central America, then reform out in the eastern Pacific Ocean

25. Storm Damage Damages caused by these powerful storms can be divided into three categories Wind damage Storm surge Inland flooding

26. Wind Velocity Wind velocities associated with an Atlantic Ocean hurricane that is advancing towards North Carolina So wind velocity (and hence wind damage) depends on which side of the hurricane you are on

27. Wind Velocity Higher wind velocities on the right side of the hurricane will also create higher waves and a higher storm surge

28. Storm Surge & Tides The 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 Wave height adds to the storm surge

29. Hurricane Category In 1973, the Saffir-Simpson Hurricane Scale was announced by Herbert Saffir, a consulting engineer, and Dr. Bob Simpson, director of the National Hurricane Center It was created to categorized the destructive power of a hurricane This is where the term “category 4 hurricane” comes from

30. Katrina The destruction caused by Katrina in 2005 exceeded $81 billion and killed 1,836