Rolling slowdowns and delays on Interstate 84 west of Hood River are scheduled in both directions around noon Thursday for the sixth in a rock blasting series necessary to build the latest segment of the Historic Columbia River Highway State Trail. The Oregon Department of Transportation indicates the blast, one of the smallest of the series, will take place around noon near milepost 53. The rolling slowdowns will delay traffic in both directions but the delays are expected to be shorter than for previous blasts. The schedule may change due to unforeseen conditions. Further blasts may not be necessary to complete the project.