A flurry of unexpected tornadoes swept through central Iowa Thursday, injuring at least 17 people, flattening buildings in three cities and forcing a hospital evacuation. Residents, and even weather forecasters, were taken by surprise yesterday as the tornadoes hit Marshalltown, Pella and Bondurant. Alex Krull, a meteorologist with the National Weather Service in Des Moines, says forecasting models had shown only a slight chance of strong thunderstorms.
