May 12, 2004: Attica and Harper, Kansas tornadoes

Storm Chasing Event Archive > 2004 Events > May 12, 2004

May 12, 2004, known as the “Attica day” for the event’s most famous tornado, kicked off a very active and memorable 30-day period for storm chasers across the Great Plains. This day’s target was straightforward and clear-cut, with a triple point setting up near Medicine Lodge, Kansas by early afternoon. The SPC had a Slight Risk outlined for the area, with 5% tornado probabilities.

Two storms initiated near the triple point by late afternoon, and both became tornadic. The northern storm produced a brief tornado near Pratt just before getting cut off by the southern storm’s forward flank precip. During this time, the southern storm produced a high-based, slender, very photogenic tornado west of Sharon that lasted about 10 minutes.

The southern storm, now dominant and tracking generally due east along Highway 160, cycled as the Sharon tornado dissipated, quickly producing a larger tornado just south of the town of Attica. The tornado began as a truncated cone with a diffuse debris cloud at the surface. As its most mature stage, the tornado was a stout cone with a dense debris cloud composed of the red Kansas soil. The tornado moved northward, barely missing the town – but striking a home next to the highway that was lifted off of its foundation in one piece. Video captured of this incident (by Scott McPartland and others) became one of the day’s most iconic shots. As the Attica tornado was ongoing, chasers encountered baseball and softball-sized hailstones to the north and west of town.

During its next cycle, the storm produced another strong tornado, similar in appearance to the Attica tornado, right at dusk several miles to the east of the town. Some chasers missed this tornado after being blocked by the road closure in Attica where the house had been destroyed.

The storm produced two more notable tornadoes, including its strongest: an F4 near Harper. Near Anthony, yet another strong cone tornado developed after dark, clearly visible when illuminated by lightning flashes as it moved east.

19 tornado reports are logged for this day in Kansas, Colorado and Louisiana. The strongest tornado of this event was the F4 near Harper, Kansas at 8:30PM. The Attica tornado was rated F2.

Photos


LEFT TO RIGHT: Tornado near Sharon, Kansas; F2 Attica, Kansas tornado; Attica tornado rope stage; Night tornado near Anthony, Kansas, illuminated by a lightning flash

Charts


Left to right: 2100z surface chart, 00z 850mb chart, 00z 500mb chart, 12z LMN sounding

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