How Do Hurricanes Form?

What You'll Learn

• Hurricanes form over warm ocean water (at least 80F / 27C)
• Warm water evaporates and rises, creating low pressure
• The Earth's rotation makes the storm spin — the Coriolis effect
• The center of a hurricane is called the eye — calm and clear
• Hurricanes weaken when they reach land — no warm water fuel

Words to Know

Hurricane

A giant spinning storm with very strong winds

"The hurricane had 100 mph winds."

Evaporate

When water turns into invisible gas

"Warm ocean water evaporates and rises."

Eye

The calm center of a hurricane

"The eye was surprisingly calm."

Rotate

To spin around in a circle

"The Earth rotates, making storms spin."

Check What You Learned

Fun Facts

• Hurricanes form over warm ocean water >= 80F (27C)

  Source: NOAA

• Warm water evaporates and rises, creating low pressure

  Source: NASA Hurricane Science

• The Coriolis effect from Earth's rotation makes storms spin

  Source: National Weather Service

• Northern Hemisphere: counterclockwise; Southern: clockwise

  Source: NOAA

• The eye is typically 20-40 miles across, calm and clear

  Source: National Hurricane Center

• The eye wall has the strongest winds and heaviest rain

  Source: NOAA