The Shishpar glacier in northern Pakistan started rapidly thawing during a record heat wave last spring. The melted snow and ice flowed into a nearby ice-dammed lake until water levels grew too high, triggering a large flash flood that wiped out a key bridge and battered a downstream village.
This is not a unique event. Across the world's iciest regions, communities live with the looming threat of inland tsunamis - massive walls of water moving quickly and forcefully from melting glaciers, known as glacial lake outburst floods.