On April 3 and 4, 1975, during a period of approximately 36 hours, a large region in the Eastern United States was subjected to severe winds. The area affected extended from Northern Pennsylvania to Southern Virginia. The National Bureau of Standards (NBS) conducted a limited study of wind damage to buildings in, and adjacent to, the Metropolitan Washington, D.C. area.
Meteorological data indicated that the winds were somewhat less severe than those that should have been anticipated by designers. Thus, most of the observed damage reflected inadequacies in design or construction. Damage was observed in occupied buildings, as well as in buildings under construction. Damaged elements of occupied buildings included: masonry curtain walls; masonry gable walls; masonry veneer; roofs with overhangs; roofing; and cladding. Damaged elements of buildings under construction included roofs and masonry walls.
The information presented in the NBS report, "Investigation of Wind Damage in the Metropolitan Washington, D.C. Area, April 3-4, 1975 (NBS TN 909)," was intended to serve as a reference for further studies, research and recommendations.