Section 3: Tropical Storms Normally peaceful, tropical oceans are capable of producing one of Earth’s most violent weather systems—the tropical cyclone. K What I Know W What I Want to Find Out L What I Learned

Essential Questions How do tropical cyclones form? What is the life cycle of a tropical cyclone? What are the dangers associated with hurricanes? Tropical Storms Copyright © McGraw-Hill Education

Vocabulary Review New Coriolis effect tropical cyclone eye eyewall Saffir-Simpson Hurricane Wind scale storm surge Tropical Storms Copyright © McGraw-Hill Education

Overview of Tropical Cyclones During summer and fall, the tropics experience conditions ideal for the formation of large, rotating, low-pressure tropical storms called tropical cyclones. Copyright © McGraw-Hill Education Tropical Storms

Overview of Tropical Cyclones Cyclone location Favorable conditions for cyclone formation exist in all tropical oceans except the South Atlantic Ocean and the Pacific Ocean off the west coast of South America. Tropical Storms Copyright © McGraw-Hill Education

Add link to Animation from p. 355 here. Tropical Cyclones Concepts In Motion FPO Add link to Animation from p. 355 here. Tropical Storms Copyright © McGraw-Hill Education

Overview of Tropical Cyclones Cyclone formation Tropical cyclones require two basic conditions to form: an abundant supply of warm ocean water and some sort of mechanism to lift warm air and keep it rising. Tropical Storms Copyright © McGraw-Hill Education

Overview of Tropical Cyclones Cyclone formation The first indication of a building tropical cyclone is a moving tropical disturbance. When a disturbance over a tropical ocean acquires a cyclonic circulation around a center of low pressure, it has reached the developmental stage and is known as a tropical depression. Tropical Storms Copyright © McGraw-Hill Education

Overview of Tropical Cyclones Cyclone formation When wind speeds around the low-pressure center of a tropical depression exceed 62 km/h, the system is called a tropical storm. If air pressure continues to fall and winds around the center reach at least 119 km/h, the storm is officially classified as a cyclone. Tropical Storms Copyright © McGraw-Hill Education

Overview of Tropical Cyclones Cyclone formation Once winds reach at least 119 km/h, another phenomenon occurs—the development of a calm center of the storm called the eye. The eye of the cyclone is often 30 to 60 km of calm weather and blue sky. Tropical Storms Copyright © McGraw-Hill Education

Overview of Tropical Cyclones Cyclone formation The strongest winds in a hurricane are usually concentrated in the eyewall—a tall band of strong winds and dense clouds that surrounds the eye. A hurricane will last until it can no longer produce enough energy to sustain itself. This usually happens when the storm has moved either over land or over colder water. Tropical Storms Copyright © McGraw-Hill Education

Visualizing Cyclone Formation Like most storms, cyclones begin with warm moist air rising. Tropical Storms Copyright © McGraw-Hill Education

Add link to Animation from p. 357 here. Visualizing Cyclone Formation Concepts In Motion FPO Add link to Animation from p. 357 here. Tropical Storms Copyright © McGraw-Hill Education

Overview of Tropical Cyclones Tropical cyclone movement Like all large-scale storms, tropical cyclones move according to the wind currents that steer them. Tropical Storms Copyright © McGraw-Hill Education

Hurricane Hazards The Saffir-Simpson Hurricane Wind scale classifies hurricanes according to wind speed, which implies potential for flooding and potential for property damage. Tropical Storms Copyright © McGraw-Hill Education

Hurricane Hazards Damage Hurricanes can cause extensive damage, particularly along coastal areas, which tend to be where human populations are the most dense. Tropical Storms Copyright © McGraw-Hill Education

Hurricane Hazards Winds Much of the damage caused by hurricanes is associated with violent winds. Tropical Storms Copyright © McGraw-Hill Education

Hurricane Hazards Storm surge A storm surge occurs when hurricane-force winds drive a mound of ocean water toward coastal areas where it washes over the land. Tropical Storms Copyright © McGraw-Hill Education

Hurricane Hazards Hurricane advisories and safety The National Hurricane Center issues a hurricane warning at least 36 hours before a hurricane is predicted to strike. Awareness, combined with proper safety precautions, has greatly reduced death tolls associated with hurricanes in recent years. Tropical Storms Copyright © McGraw-Hill Education

Review Essential Questions Vocabulary How do tropical cyclones form? What is the life cycle of a tropical cyclone? What are the dangers associated with hurricanes? Vocabulary tropical cyclone eye eyewall Saffir-Simpson Hurricane Wind scale storm surge Tropical Storms Copyright © McGraw-Hill Education