Glacial outburst floods aren't a new phenomenon in Alaska, but climate change is scrambling the geography of risk.

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.

Sections of Alaska’s capital city are bracing for the arrival of what could be record floodwaters due to rainwater and snowmelt flowing downstream from a basin dammed by the Mendenhall Glacier.