Observe: Thunderstorms Are Caused by Air Movement

The movement of hot and cold air drives many weather systems.

Thunderstorms are one of nature's most beautiful, and most scary, weather phenomena.  They can be destructive.  Thunderstorms often come with violent winds and can even produce tornados.  The movement of air from thunderstorms can cause much damage, but it is the movement or air that creates thunderstorms to begin with.  How does movement of air create thunderstorms?

Understanding the air movement involved in thunderstorms is easier if we think of the storm as a three-stage "life cycle":

Stage 1:

On a hot day, the Sun heats the air.  The hot air rises rapidly in an updraft, carrying moisture with it.  Cooler air rushes in at ground level to replace the warm air that is rising.  This is why thunderstorms always have strong winds nearby.

Stage 2:

When the hot air gets very high, it cools.  This cooling makes water droplets form.  You can see this in the air as very tall, dark clouds.  When the water in the cloud becomes too heavy for the updraft to keep in the air, it begins to fall as rain.

Stage 3:

As the rain in the thunderstorm continues to fall, the air in the cloud continues to cool.  Cool air is denser and falls to Earth, which creates a strong downdraft at the end of the storm.

You can see why the movement of hot and cold air has such an important role in the formation of thunderstorms.

How do temperature differences contribute to severe weather?

Resources

Notebook

Click here to download the instructions for this activity. Save to your Weather Notebook.

  Skill Builder

Click a link below to learn how to:

construct a diagram in Google Docs


Thunderstorms are common to Alberta, and stormy weather can lead to a tornado.  Predicting storms and tracking them is important.  Because warning people about storms can save lives, learning as much about weather as we can is important.


  Video

Watch this BrainPop video - How tornadoes form

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