A wave of water that gushed out of an Alaskan glacial lake and sent a river surging to a new record level is causing flooding issues in the state capital of Juneau for the third consecutive August.

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.

Meltwater is escaping from a basin that is dammed by a glacier - prompting fears of a deluge in state capital Juneau.