A year ago I spent a couple of frigid days in Cedar Rapids, Iowa, reporting a story on 2007 Masters champion Zach Johnson, a Cedar Rapids native. I didn’t go there to meet Johnson (that came later, in Florida). I went to better understand the importance of his upbringing, which perhaps more than anything, Johnson has said, keyed his remarkable rise. Defined by hardworking, decent folks, Cedar Rapids happily lives up to many of the clichés you might attach to the Midwest. It’s a humble town that doesn’t make much national news, if only that still held true.

In the middle of June, Cedar Rapids drowned. While Johnson was in San Diego for the U.S. Open, three days of heavy rain flooded the Cedar River and submerged the city under water. You probably saw the images—pick-up trucks bobbing, a family stranded in a dingy, the usual frightening flood footage. Water covered nearly 10 square miles of the town and the estimated damage was in the vicinity of $1.5 billion.

The devastating aftermath is poignantly detailed in a new nine-minute documentary, Three Days in June, narrated by Johnson himself. (You can view the film at embraceiowa.com.) A PGA Tour film crew shot Johnson when he returned to his hometown in September. His sorrow is palpable. “The silence is the worst part,” Johnson says, as he wanders a barren street, shaking his head in disbelief.

There are some uplifting moments, including clips of Johnson’s parents and other townspeople speaking about the resolve of Cedar Rapidians and how they will overcome the destruction. But mostly it’s an eye-opening reminder of a story that has dropped off the national radar—stunning given that the flood was among the worst natural disasters in U.S. history.