The Z_dr column signature was studied using data collected by KOUN, the prototype polarimetric WSR-88D at the National Severe Storms Laboratory in Norman, Oklahoma. Eight storms from two severe weather events during the Joint Polarization Experiment (JPOLE), 8 May 2003 and 9-10 May 2003, were chosen for detailed study. The height above the 0°C level, width, location, maximum values of Z_dr within the column, and time of appearance were recorded for each of these storms. There were differences in the height of the Z_dr column from storm-to-storm, but when beamwidth error was considered the differences were not identifiable. The width of the Z_dr column also varied from storm-to-storm, with the widest column nearly 6.3 km across and the narrowest 2.2 km across. When a bounded weak echo region was present, the Z_dr column was usually co-located with it. Z_dr values within the column ranged from 0.9 dB to 5 dB. Comparisons were made between the time of the first Z_dr column appearance and the first National Weather Service-issued severe thunderstorm warnings and severe weather reports. The appearance of the Z_dr column preceded the first warning by an average of 15 minutes and the first severe weather report by an average of 39 minutes.