Abstract: Employee #1, a crane operator, and coworkers were installing precast concrete panels at a warehouse under construction at the Marvin Window Factory in Warrand, MN. Panel #3 was in place and welded to the sill. It had a safety jack on the east side but no jack could be put on the west side because the crane was in the way. Due to the way the building was being constructed, there was a wind tunnel effect. Apparently, a gust of wind caused the panel to move and break loose from the safety jack. The panel fell toward the outside, striking the crane and pinning Employee #1 behind the controls. He was struck a glancing blow, sustaining fractured ribs and a collapsed lung. He was expected to return work in about 30 days.