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.

Mendenhall River crested at a record-setting 16.65 feet deep as of 7:15 a.m. Alaska time (12:15 Eastern), and began to empty, according to National Weather Service experts. The water level had fallen to about 8.