Flood in Lower Koyukuk Valley, Alaska

An ice jam on the Koyukuk River near Hughes impounded a significant volume of water. This caused water levels to submerge properties in the lower sections of the community, directly impacting local residences, school property, and the airport. Local residents and members of the Alaska State EOC indicated that the ice set up late Friday night and then released Saturday afternoon. However, a secondary jam set up soon after which was responsible for sending most of the water into the community. Numerous families were sheltered at the local community hall which is located on higher ground.

The 2026 spring breakup along the Yukon River was highly dynamic, defined by a combination of thermal ice decay and severe mechanical ice jams. Because of an exceptionally cold winter and a cool spring, the river ice was thicker than normal and had not deteriorated significantly before the main breakup front arrived. Early-season flooding was driven by localized snowmelt and ice jams on independent river systems and upper sections of the Yukon River.