That's how witnesses described feeling after three people slipped into the foamy waters of the Big Sioux River, in the middle of a Sioux Falls park.

CNN: March 16, 2013 -- Updated 0041 GMT (0841 HKT)

The drama unfolded Thursday evening amidst the 123 acres of Falls Park, which is named -- like the city of Sioux Falls itself -- for the series of picturesque Big Sioux River waterfalls that run through it.

CNN: March 16, 2013 -- Updated 0041 GMT (0841 HKT)