Tornadoes and Hurricanes: How They Form

How Hurricanes Form

Hurricanes form over warm ocean waters and grow into massive storms through a powerful energy cycle.

Warm Ocean Waters: Provide the energy that fuels hurricanes by heating the air above, which then rises and creates a low-pressure center.

Low Pressure and Convection: As warm, moist air rises, it cools, condenses, and forms clouds and thunderstorms. This process creates a low-pressure area at the center, drawing in more air.

Coriolis Effect: Due to Earth’s rotation, incoming air rotates around the low-pressure center, forming the spiral structure.

Structure: Features include the calm eye, the surrounding eyewall where the strongest winds occur, and the rainbands that extend out.

 

How Tornadoes Form

Tornadoes emerge from powerful thunderstorms when contrasting air masses interact in extreme ways.

Supercell Thunderstorms: Tornadoes often develop within these rotating storms where strong updrafts exist.

Wind Shear and Instability: A sudden change in wind speed or direction with height (wind shear) combined with unstable, moist air can create a rotating updraft called a mesocyclone.

Formation Process: As the mesocyclone tightens, it may produce a funnel cloud that eventually touches the ground to become a tornado.

Scale: Tornadoes are much smaller in scale than hurricanes but can have extremely high wind speeds over a very narrow area.

 

Fun Facts

Here are some interesting facts about hurricanes and tornadoes:

• Some hurricanes can be over 600 miles wide, and their winds can exceed 150 mph.
• The eye of a hurricane is usually calm, even though the eyewall is extremely violent.
• Tornadoes can form in just a few minutes and have wind speeds that exceed 300 mph.
• The state of Oklahoma experiences more tornadoes per square mile than any other place in the world.

 

Review

Let’s quickly recap what we learned about hurricanes and tornadoes:

• What fuels a hurricane? Warm Ocean Waters
• What is the calm center of a hurricane called? Eye
• What effect makes hurricanes rotate? Coriolis
• What type of storm often produces tornadoes? Supercell Thunderstorms