Flood — Upper Koyukuk Valley, Alaska

2025-08-28 to 2025-08-31 · near Allakaket, Upper Koyukuk Valley, Alaska

Event narrative

Emergency management personnel with the Tanana Chiefs Conference and local officials from Allakaket reported a prolonged moderate to major flood that surrounded most of the lower community, Old Town, and the old runway. Several roads including the airport access road and Main Street washed out. The river officially crested at 64.54 feet on August 31st.

Wider weather episode

A prolonged period of deep moist southwesterly flow from the North Pacific ocean, otherwise known as an Atmospheric River, produced several days of heavy rainfall along the south slopes of the Brooks Range. Over about a 5 day period total rainfall of three to six inches resulted in considerable flooding for the Koyukuk and it's tributaries. In addition this southwest flow also resulted in very strong winds through the Alaska Range passes.

View location on OpenStreetMap → (66.5494, -152.6848)

Source: NOAA Storm Events Database, event_id 1293180. Narrative written by the NWS forecast office that issued the report.