Weather Imagery

What causes thunder?

Thunder is caused by the rapid expansion and contraction of the air surrounding a lighting bolt. On average, a lightning bolt is about 5 times hotter than the surface of the sun or about 50,000°F! This causes the air around the lightning bolt to become super heated and as a result, the air rapidly expands in fractions of a second. However, the air doesn’t stay super heated for long and quickly dissipates the heat in fractions of second. It’s this rapid expansion and contraction of the air that creates a compression wave we hear as thunder. Contrary to what some think, thunder is not caused by the lightning bolt “breaking the sound barrier”. If this were true, then every time we turned on a light in the house we would hear a sonic boom!

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