On 3 May 1999, a major storm passed through the mid-west, spawning at least 76 tornadoes, and killing more than 50 people. The Oklahoma City, Oklahoma metropolitan area was the hardest hit, with 43 fatalities, and 10,000 homes destroyed or severely damaged. The losses due to damage caused by the storm exceeded $1.1 billion. The National Weather Service rated the tornado that struck Oklahoma City as a F5 on the Fujita tornado intensity scale.
In the aftermath of the tornadoes, the NIST sent a team to investigate the damage to engineered structures in the Oklahoma City area. The damage reconnaissance included an aerial survey of the largest tornado tracks in central Oklahoma and a two-day ground survey. The ground survey included visits to eight damage sites with twelve damaged engineered structures.
The report provides an overview of observed damage to engineered structures, including schools, hotels, and industrial buildings, reports observations on debris accumulation, briefly discusses the tornado rating, and recommends actions to reduce future losses.NIST REPORT: Reconnaissance Report on Damage to Engineered Structures During the May 1999 Oklahoma City Tornado (NIST IR 6899, August 2002)
Oklahoma Tornado 1999, Damage to Southern End of Front Section of Kelly Elementary School. (Photo credit: NIST)