An Oklahoma Tornado Rewrites the Rule Book

It was an anticyclonic tornado, meaning that it rotated clockwise rather than counterclockwise. Overshadowed by the mighty EF4 and EF3 tornadoes that tore across south-central Oklahoma last Monday, May 9, another less damaging twister--from the same thunderstorm--has left seasoned scientists both astonished and fascinated, breaking a long-held rule about where tornadoes form within a supercell thunderstorm.

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