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.

Residents in some parts of Juneau prepared to evacuate ahead of what could be a record surge of flooding as rainwater and snowmelt in a huge basin dammed by Alaska’s Mendenhall Glacier started to flow downstream toward the capital city.

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.