Dear Tom,
How common is biological scatter in non-precipitation weather radar echoes?

—George Kalinka

Dear George,
It’s very common, with biological scatter being detected by radar on almost a daily basis. The National Weather Service’s Doppler radars are extremely sensitive and have a dual-polarization mode that allows beam transmission in both the horizontal and vertical planes. For meteorological purposes, the dual-pol mode produces better precipitation estimates, improves the ability to distinguish between rain, hail, sleet, and snow, detects tornado debris, and even identifies icing conditions that could impact aircraft. This sensitivity also allows the radar to detect airborne birds, bats, and insects, smoke, wind farms, and other ground clutter. There have also been documented studies where radar has detected swarms of mayflies and grasshoppers.