US 321 south of Blowing Rock was tied up with an injury accident that occurred sometime just before 5am.  Caldwell dispatch reported the north-bound lanes were blocked near the northern end of the four lane section, near the start of the construction zone, and the SHP said that Clyde Lefever, 36, of Hudson may have hit a slick spot. His Nissan sedan slid sideways, struck the rock retaining wall, then spun twice before coming to rest across both north-bound lanes.  Blowing Rock Fire/Rescue arrived on the scene just after 5 to work the wreck; Caldwell EMS transported Lefever to Watauga Medical Center suffering a large gash to his head that required stitches. He was cited for Failure to Maintain Lane Control.