Each summer in the mountains above Juneau, Alaska, meltwater from the massive Mendenhall Glacier flows into mountain lakes and into the Mendenhall River, which runs through town.

These floods, which began more than a decade ago, have become increasingly destructive in recent years and now pose a persistent summertime threat. This time, Alaska’s capital city fortified itself against the floodwaters.

Because the flooding has been a growing concern, city officials have installed emergency flood barriers along several miles of riverbanks.