Two large glacier detachments occurred at Flat Creek glacier in Alaska, releasing a huge amount of ice and debris. The detachments were caused by high meltwater input, erodible glacier bed, inefficient drainage, and increased ice stresses. The glacier remained unstable due to water inputs, leading to a second detachment in 2015. Similar events in Tibet suggest that high meltwater inputs drive glacier detachments. With increasing temperatures, glacier detachments may become more frequent, posing risks in glaciated regions.