Published on: May 25, 2009 at 9:00 AM

One year ago today…May 25, 2008…

The tornado that struck the communities of Parkersburg, New Hartford and Dunkerton in Iowa tornado was rated as an EF 5. This correlates to wind speeds up to 205 MPH on the Enhanced Fujita Scale at the locations of maximum damage. This is the first EF5 tornado in Iowa since the Jordan tornado of June 13, 1976.

The large and destructive tornado moved across Butler and Black Hawk counties. The initial touchdown occurred near the Butler and Grundy county line, 2 miles south of Aplington at 4:48 pm CDT and quickly grew in size and intensity as it approached Parkersburg. The tornado was nearly 3/4s of a mile wide as it moved through the southern end of the town at 4:59 pm CDT. Significant structural damage occurred, including 100 to 200 homes destroyed.

The tornado maintained size and intensity as it move towards New Hartford. At 5:09 pm CDT the storm moved just north of that city once again causing significant structural and tree damage. The tornado weakened around 3 miles east of New Hartford with lesser damage as it moved east to north of the Waterloo and Cedar Falls area.

Significant straight line winds occurred along and just south of the tornado track with preliminary estimates of 90 to 100 mph. This damage was likely the result of the rear flank downdraft, which accompanies the mesocyclone. The tornado then grew in size to near 1.2 miles wide north of Dunkerton causing substantial damage to a farmstead there. The tornado lifted just before entering Buchanan County.