We don't know yet how strong the Evansville tornado was. Here's how the classification system works.

Tornadoes are classified using what's known as the EF scale, which factors in estimated wind speeds and related damage.

In 2005 , 62 tornadoes hit Wisconsin , which remains the record for the most tornadoes in a single year from the last 30 years .

The deadliest tornado to hit Wisconsin was an EF-5 that hit Colfax on June 4, 1958 .