The properties of the melting layer in rain showers were studied using polarization lidar and W-band Doppler radar systems, and supporting research aircraft. The changes in hydrometeor scattering behavior at wavelengths ranging from 0.532 &mgr;m to 3.2 mm during the snowflake-to-raindrop transition generally conform with the expected features of the bright band phenomenon, except that a narrow lidar returned signal minimum, or dark band, was observed ~750 m below the freezing level. This new feature is found where Doppler velocity and depolarization data indicate raindrops, and, ironically, also occurs at the position of the W-band radar reflectivity bright band. Drawing from laboratory laser scattering studies and Mie theory, we conclude that the particles responsible for the lidar dark band are inhomogeneous ice-containing raindrops formed by the structural collapse of severely melted snowflakes. ¿ American Geophysical Union 1995