At least three tornadoes touched down in Oklahoma City on Saturday, part of a series of "life-threatening" twisters predicted. No injuries have been reported. The outbreak is expected to start late in the day and target the I-35 corridor, which includes Oklahoma City and Wichita, Kan., but forecasters have extended the danger area as far north as Minnesota. A tornado hit Norman, home of the University of Oklahoma, Friday, causing structural damage but no serious injuries.
