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. Since 2011, scientists and local officials have kept a close eye on one lake in particular: Suicide Basin,

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.