Many people are without power across the state, police said.

Storms damaged a mall and a bank and collapsed the roof of a fire station in Kokomo, Indiana, said Larry Smith, emergency management director in Howard County.

Some houses had their roofs torn off when a tornado hit the area, he said.

Officials in Kokomo declared a state of emergency and closed schools for Monday, according to the city's Twitter account.

This is a particularly dangerous situation, the National Weather Service said in a bulletin released Sunday morning.

And a tweet from the weather service in northern Indiana was even more ominous: "The worst decision you could make today is to ignore a severe/tornado warning. These storms will be nasty."

A tornado watch means that weather conditions exist that can produce tornadoes and severe thunderstorms. Conditions are favorable for long-tracked, significant tornadoes across this watch area, the Storm Prediction Center said.

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