DES MOINES, Iowa (AP) — Authorities say flash flooding is occurring across several counties in northeast Iowa after a second night of heavy rains.

The National Weather Service says storms are impacting the areas that saw downpours on Wednesday night. A flash flood warning has been issued for parts of Story, Butler, Cerro Gordo, Franklin and Bremer counties until early Friday morning.

Floyd County was hardest hit with rainfall totals of nearly a foot in some areas (a report from north of Powersville had a Thursday total of 11.25 inches).

In Clarksville, an unknown number of evacuations are underway after the weather service says a levee on the Shell Rock River failed. Emergency managers also reported a number of closed county roads due to high water.

Further downstream, the Des Moines Register reports residents of Cedar Falls, Waterloo and Cedar Rapids are preparing for what could be the worst flooding since 2008, when the Cedar River displaced thousands of people.