The National Weather Service says the tornado that roared through Ottawa, Illinois, and the small village of Naplate packed winds up to 155 mph.
The weather service rated Tuesday's tornado, which caused severe damage in Naplate and left one dead in Ottawa, an EF-3 on the Enhanced Fujita scale.
The weather service did not rule out the possibility that other tornados may have touched down in the area southwest of Chicago. Baseball sized hail was also observed in the area.
An EF-1 tornado was reported near the northern Illinois town of Oregon. Straight line winds of around 80 mph following the tornado caused additional damage.
In southern Illinois, an apparent twister of undetermined strength near the town of Crossville killed a 71-year-old man and injured his wife.
