Floods drive people from homes in Iowa as much of US swelters in extreme heat

Residents rescued by boat as Governor Kim Reynolds declares disaster in 21 counties in north of state

Floodwaters forced people out of their homes in parts of Iowa, the result of weeks of rain, while much of the US longed for relief on Saturday from yet another round of extraordinary heat.

Sirens blared at 2am in Rock Valley, Iowa, population 4,200, where people in hundreds of homes were told to get out as the Rock River could no longer take rain that has slammed the region. The city lacked running water because wells were unusable.