When mountain permafrost thaws and glaciers melt, glacial lakes can become lethal flood risks for anyone downstream.

Byers, University of Colorado Boulder In mountain ranges around the world ... Juneau, Alaska, has been hit by several flash floods in recent years from a glacial lake dammed by ice on an arm ...

Too much water behind these dams or a landslide into the lake can break the dam, sending huge volumes of water and debris sweeping down the mountain ... hit by several flash floods in recent ...

In mountain ranges around the ... have experienced glacial lake outburst floods of one type or another. Juneau, Alaska, has been hit by several flash floods in recent years from a glacial lake ...