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.

One of Alaska's most populated cities is bracing for potentially catastrophic flooding as a basin dammed within the Mendenhall Glacier has started to release water.

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.