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Fast Facts
 

Links, Facts and Statistics for the April 26, 1991 Great Plains Tornado Outbreak

  • After April 29, 1984 when a violent tornado struck Mannford (near Lake Keystone), there were no violent tornadoes in the state for almost 7 year until the April 26, 1991 tornado outbreak. This is the longest period of time that the state has gone without a violent tornado since tornado data began to be regularly compiled in 1950, and likely dating back to statehood.

  • Within the Oklahoma and north Texas counties currently served by the NWS Norman, there were no violent tornadoes for almost 10 years after the Binger tornado of May 22, 1981. Unfortunately, this streak also ended on April 26, 1991.

  • In April of 1991, the Norman, Oklahoma, WSR-88D (NEXRAD) was the only WSR-88D that was active in the U.S. While it had not yet been cleared for use in everyday operations. the WSR-88D was used by forecasters at NWS Norman  to interrogate supercell thunderstorms in north central Oklahoma. The WSR-88D in Norman proved that increased warning lead times – especially for initial tornado touchdowns – would likely result from a new national radar network. Important storm-scale features, including mesocyclones and various reflectivity features, could be clearly seen in storms even great distances from the radar. Using this new technology, NWS Norman was able to issue most Tornado Warnings before any tornadoes touched down as a result of a storm’s appearance on the WSR-88D. Twenty-four minutes of lead time was provided in one case.