Have you ever heard someone talk about “the calm before the storm”? If you’ve seen storms up close, you know there’s usually nothing calm about them! So what are people talking about?
The calm — sometimes called a lull — before the storm is a phrase often used to refer to a period of peace or rest that comes right before a time that is very busy or hectic. When you think about it, it just makes sense.
If you’re suddenly very busy with activities or lots of excitement, the period of time before that started would naturally be peaceful by comparison. There’s actually a little more to it than that, though.
The calm before the storm got started as a phrase sailors used to refer to an actual weather phenomenon they observed often at sea. You may have noticed this phenomenon from time to time, too.
For example, have you ever been playing in your backyard on a warm summer day? As you’re having fun, you suddenly notice that the world around you seems quieter. The air around you is still and even the birds and other animals seem to have disappeared.
Before long, you start noticing changes. Clouds appear. Winds increase. You head for the house just as raindrops begin to fall from the sky. As you look out the window at the rain falling, you might wonder, “Why did it get so calm right before the storm?”
That’s the same question that sailors and other people have asked for thousands of years. Fortunately, the science behind storms can help us understand the calm that sometimes comes before them.
The fuel that storms run on is warm, moist air. As a storm approaches, it pulls warm, moist air from the atmosphere all around it. It can even pull air from the direction in which it’s traveling.
As air is drawn into a storm, it leaves a low-pressure vacuum in the area it came from. The warm, moist air travels up through storm clouds, cooling and condensing as it feeds the storm clouds.
However, updrafts quickly push the air out of the tops of the storm clouds. Once it gets pushed out, it descends back down toward Earth, drawn by areas with low-pressure vacuums (or, in other words, right back where it came from!).
As the air descends, it gets warmer and drier. This warm, dry air that settles back down to Earth is stable. As it covers an area, things tend to get quiet and calm. This is the calm before the storm!
Of course, things don’t always happen this way. There are many different types of storms that can behave in many different ways. Sometimes storms aren’t preceded by calm. Instead, they announce their arrival with wild winds and cracks of thunder.