The fourth-largest outburst flood in Juneau’s history crested in August. Soon after, Eran Hood stood at the edge of an enormous empty basin in the mountains above the city.

Just a day or so before, the basin had been full of 16-billion gallons of water.

“This right here is the source of all the trouble in Juneau,” said Hood, an environmental scientist at the University of Alaska Southeast who has been coming to this spot for 15 years to study an annual flood triggered by rapid melting on the Mendenhall Glacier.

Glacial floods are increasingly dangerous around the world. Two weeks after Juneau’s flood subsided, [a weakened ice sheet collapsed](https://www.wbur.org/hereandnow/2026/08/28/nepal-glacier-flood) in the Himalaya and triggered catastrophic floods and landslides in Nepal.

Something similar [is happening in Alaska](https://juneauflood.org/#/home).

Each summer, a natural reservoir that’s formed along the edge of the Mendenhall Glacier fills with water from melting ice. The glacial lake has an unfortunate name — [Suicide Basin](https://www.weather.gov/ajk/suicidebasin), likely a reference to the imposing terrain, Hood said.

Three of the basin’s sides are towering bedrock cliffs. The fourth side is formed by the glacier itself, which creates an ice dam that holds the water back most of the year. But as summer wears on, the pressure builds to a breaking point. The water eventually floats the glacier, and an icy torrent begins to slip beneath the ice.

The melting Alaska glacier that wears the scars of climate change