On April 22, 2011, a violent EF4 tornado, with winds of 170 mph (270 km/h), struck the St. Louis metropolitan area.[2] The tornado, which was the strongest to hit St. Louis County or City since January 1967, moved through many suburbs and neighborhoods, damaging and destroying many homes and businesses. The worst damage was in the Bridgeton area, where a few homes were completely leveled.[3] In its 21.3mile (34.3 km)[4] track across the St. Louis metropolitan area, the tornado damaged thousands of homes, left thousands without power, and caused heavy damage to St. Louis Lambert International Airport, closing it for nearly 24 hours.[5] The tornado crossed into Illinois and tore the roofs off homes in Granite City before dissipating. The tornado was part of a period of high tornado activity that preceded the 2011 Super Outbreak.