Balloon Bombs

We mention the jet stream almost everyday in our forecast posts. However, we never really mention what the jet stream is or how it was discovered.

Jet streams are described by the National Weather Service as follows:

Relatively strong winds concentrated in a narrow stream in the atmosphere, normally referring to horizontal, high-altitude winds. The position and orientation of jet streams vary from day to day. General weather patterns (hot/cold, wet/dry) are related closely to the position, strength and orientation of the jet stream (or jet streams). A jet stream at low levels is known as a low-level jet.

So, how was the jet stream discovered? Like many things discovered in meteorology, it happened during a war.

In World War II the Japanese were mapping out air currents by launching balloons attached with measuring instruments from the western side of Japan and picking them up on the eastern side. Following the trajectory of these balloons, one could effectively map out the jet stream.

So, what did the Japanese do during WWII when they discovered the jet stream? They didn’t try to more accurately predict the weather. Instead, they attempted to make bombs that hung from these balloons in an attempt to give them an advantage during the war.

At first, the Japanese didn’t have much success. However, there was one instance when an estimated 1,000 were found across North America. Overall the strategy wasn’t very effective, but the jet stream was discovered in the process, which is fundamental in today’s forecasting methods.

To read more information about these Balloon Bombs, check out this detailed article by National Geographic.