Hurricanes are tropical cyclones that form over warm ocean waters between 5 and 30 degrees north or south of the equator. For a hurricane to form, certain conditions must exist including low to medium winds blowing in the same direction, ocean surface temperatures over 80 degrees F down to 150 feet deep, and a moist lower atmosphere. Hurricanes form as the warm, moist air over the ocean rises, condenses to form clouds and water vapor, and rotates due to the Coriolis effect from the Earth's rotation, fueling the storm through this cyclical process and gaining energy from the sun-heated ocean waters.

1. Hurricanes

3. What is a hurricane?
 Hurricanes are tropical cyclones.
 They form in the southern Atlantic Ocean,
Caribbean, Gulf of Mexico, and eastern
Pacific Ocean.
 Their winds spiral outward in a
counterclockwise, circulation pattern.

4. What conditions must exist for a
hurricane to form?
 Low to medium winds blowing in the same
direction
 5–30 degrees north of the equator in the ocean
 Ocean surface temperature of greater than 80
F that extends down to about 150 feet deep (50
m)
 Lower atmosphere must be moist

5. How do hurricanes form?
 The air mass above the tropical waters takes on the
temperature and humidity of the water beneath it.
 Incoming winds force the air upward.
 The warm, moist air rises, forming water vapor and
clouds.
 Above the storm, the winds flow outward.
 Outside winds blow inward, and the cycle repeats.

6. How do hurricanes move?
 Hurricanes turn to the right, away from the
equator, because of the Coriolis Effect
caused by Earth’s rotation.
 You will learn about this phenomenon later
in the lesson.

7. Where does the energy for a
hurricane originate?
 The Sun heats the oceans.
 Warm air rises, and as it cools, it
releases energy, fueling the hurricane.

8. Why don’t hurricanes form in
higher latitudes?
 The temperature of the oceans is not
warm enough.
 The distance is too far from the
equator.

9. Hurricane Katrina

11. Reflective Question
How do oceans play a role in the
development of weather systems including
hurricanes?