When Doppler radar first arrived in the area known affectionately to Texans as the Hill Country, the local television station meteorologists were understandably eager to show off the weather forecasting capabilities of their newest toy. Unfortunately, they got off to a less than impressive start. Night after night that summer, evening thunderstorms were forecast but failed to appear.
This created distrust within the populace and confusion among the weather men and women. Eventually, someone figured out that Doppler couldn’t tell the difference between a microwave reflected by water droplets in the atmosphere and Mexican free-tailed bats (Tadarida brasiliensis) emerging from nearby Bracken Cave.
How many bats does it take to confuse Doppler radar? About 20 million.