Black Hawk County Tornado

During the evening of May 11, 2000, a supercell thunderstorm contained a mesocyclone that produced tornadoes and large hail along with heavy rain, passed over extreme northeast Grundy county, southeast Butler county, southern Bremer county, and northern Black Hawk County of northeastern Iowa. Several farmsteads, homes, and powerlines were destroyed along and just north of Highway C66, or Dunkerton Road.

The supercell storm and associated mesocyclone briefly produced a small tornado two miles south of New Hartford, or in extreme northeast Grundy County. Then, the storm turned more to the right, following a due east path, tracking just north of Cedar Falls and the Waterloo Airport.

Intermittent damage began approximately one mile northeast of North Cedar with strong F3 damage occurring based upon the Fujita Damage Scale for tornadoes with the range from F0 (weak) F5 (incredible damage). At this location, one woman received severe injuries even though she took shelter in the basement of her home.

From there, the mesocyclone continued east approximately four miles, either producing intermittent touchdowns or possibly two or more tornadoes at once, each at various points in their lifecycle. During this timespan, destruction was not evident or minor with the path on the order of one to two hundred yards at times.

The next cluster of destruction, including powerlines, minor damage to a nursing home, and to farmsteads and homes occurred mainly on the north side of Highways C66 and 63. At these locations, damage estimates range from F0 to F2 with the tornado path around a quarter mile in width.

The next widespread cluster of damage could be found beginning approximately three miles east of the intersection of Highways C66 and 63. At this time the tornado began to widen, reaching up to a half mile wide (possibly wider) and producing damage to homes and other structures rated F3 at times. Certainly there was damage at these locations rated from F0 to F2 as well.

From this location, the tornado seemed to rapidly dissipate although there was some relatively minor damage to a grain elevator and trailer on the southwest edge of Dunkerton. Radar indicated the mesocyclone was located well north of this damage, thus this small cluster of damage may be attributable to rear flank downburst winds.

Click here to see the weather maps for this day.
Click here to see the path of the tornado.