Type Tornado outbreak Tornadoes confirmed 21 Duration of tornado outbreak 2 hours, 5 minutes Start date April 30, 1967 | Duration April 30, 1967 Max rating Damage $9 million dollars Number of casualties 13 | |
 | ||
The 1967 Iowa–Minnesota tornado outbreak was a tornado outbreak that affected portions of Iowa and southern Minnesota on Sunday, April 30, 1967. The outbreak spawned a total of 21 tornadoes, resulting in 13 deaths and 80 injuries. Local area residents refer to the day as "Black Sunday."
Meteorological synopsis
By mid-afternoon on April 30, a surface low pressure area was centered in Pierre, South Dakota. Several fronts stretched from the low pressure area with a stationary front located from north of Sioux Falls, South Dakota to near LaCrosse, Wisconsin. A warm front extended from south of Sioux Falls to near Des Moines, Iowa and St. Louis, Missouri. Between the two fronts, air temperatures had warmed into the 60s and low 70s and dew points in the 60s. Winds were quite strong in the area, with speeds from 15 to 25 mph from the east-southeast. By early evening, the warm front had moved to near the Minnesota-Iowa border. By 6:00 pm CDT, tornadoes began to develop along and just north of the warm front as it moved northward through northern Iowa and into southern Minnesota.
The towns of Albert Lea and Waseca were hardest hit.