A powerful surge of glacial meltwater is once again testing Juneau's resilience, and this time, the ripple effects could reach well beyond city limits — impacting thousands of travelers headed to Alaska’s capital by cruise ship.

This year, a giant wall of reinforced sandbags erected with the help of the U.S. Army Corps of Engineers held back the worst of the flooding in Juneau, to residents' great relief.

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.

The all clear has been given and residents have been allowed to return to their homes in Alaska’s capital of Juneau after a glacial lake outburst sent debris-filled water rushing down the Mendenhall River on Tuesday night and Wednesday morning.

A water basin in Alaska is overflowing its ice dam, the Mendenhall Glacier, and flooding the state capital, Juneau. Experts expect the likely record-breaking event to peak today, and officials have asked residents in parts of the city and borough to evacuate.