More than 2,200 people were without power Tuesday night as severe weather struck many northern Iowa counties. Alliant Energy reported the outages near Clear Lake, Mason City and Manly, as a line of strong thunderstorms blew through southern Minnesota, with the hardest hit area along the I-35 corridor north of Owatonna where strong winds are blamed for tipping over at least nine semi-trucks on the freeway. The National Weather Service also received reports of numerous trees being uprooted in an area near Faribault, and a tornado watch was issued for a wide area of south-central Minnesota that included the Albert Lea and Owatonna areas.