Dual-pol debris balls Posted in Perspectives, Photo of the Month on May 7, 2012 by Susan Cobb. A debris ball from a tornado is detected by dual-polarized radar near Huntsville, Ala. Related Articles:NSSL scientists study tornadoes in their own backyardSignificant Paper: Automated Detection of…Dual-pol radar captures image of debrisNSSL radar team returns from debris flow projectShare this: