Per the SPC Database, 14 tornadoes occurred on March 13, 1990 in the state of Iowa. The strongest, an F4, traveled 19 miles from Prairieburg in Linn County to Worthington in Dubuque County. It was on the ground for 30 minutes. The max width was 200 yards. There were no injuries or fatalities.
Per Storm Data, the hardest hit area was Worthington. 26 homes and businesses were damaged and 13 were destroyed. The tornado was approximately 1/2 mile wide as it approached Worthington. The width was down to about 2 blocks in town. South of Hopkinton, 2 farm houses were destroyed along with several vehicles. Over $1 million damage to a farm in Castle Grove Township. Four other rural homes were destroyed.