Radar-scope patterns at the time of known tornado occurrences were examined. There seems to be a good correlation between tornadoes and an echo pattern called a LEWP (Line Echo Wave Pattern). Many of these LEWP's were observed without reports of tornadoes or large hail. In about 75 per cent of the confirmed cases of tornadoes, their occurrence could be associated with a line of echoes. Individual echo trajectory convergence predominated in the remainer of cases.