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.

A huge basin of rainwater and snowmelt dammed by Alaska’s Mendenhall Glacier has started to release, sending a potentially record surge of flooding toward parts of Juneau.

Officials in Alaska have advised residents to evacuate the state's capital city Wednesday as a melting glacier is expected to cause major flooding.