Tornado hits Norman, Okla., causing minor injuries

Last Updated 7:43 a.m. ET,/I>

(AP) NORMAN, Okla. - Officials say a tornado that touched down near the University of Oklahoma campus in Norman caused a few minor injuries and some property damage.

The National Weather Service confirmed that a twister touched down Friday afternoon near the campus and a state highway.

Norman Regional Hospital spokeswoman Kelly Wells says about 10 people were treated for "bumps and bruises."

Storm forecasters: "Catastrophic" damage possible in Kansas, Missouri

Deputy Fire Chief Jim Bailey says the tornado damaged several homes and buildings in the city of about 100,000 residents 20 miles south of Oklahoma City.

University spokesman Michael Nash says students and non-essential personnel at the weather service's offices on the campus were ordered to remain indoors due to a tornado warning.

Damage was relatively slight from the twister, CBS News correspondent Dean Reynolds reports, but according to the National Weather Service, it could be the first of many more to come.

The Storm Prediction Center says 5.5 million Americans fall under the scope of Saturday's coming storm system which they call a "high-end life-threatening event."

Forecasters sent out a high-risk alert a full day ahead of the system that now jeopardizes areas from Iowa to Texas. They spoke of the need to have a plan to take shelter and to stay alert to the latest bulletins.

"We want to make certain that we do every effort to make sure people receive those, can act on those and can make themselves safe," National Weather Service meteorologist Mike Foster told CBS News.

It has been an unusually active and deadly spring; this March, said Reynolds, was the fourth deadliest on record.