Flood — Lower Kuskokwim Valley, Alaska

2021-05-04 to 2021-05-07 · near Aniak, Lower Kuskokwim Valley, Alaska

Event narrative

This ice jam was caused by some of the thickest ice on the river this winter - some local reports indicated that it was greater than 50 thick (most other reading along the Kuskokwim from last year are around 36). Ice became thicker in this region because of freeze up ice jams, where many layers of frazil ice accumulated. When the breakup front moved to below Aniak, this thick ice jammed. It held for 5 days and slowly backed up water to Aniak, and Aniak was on the verge of flooding from the back sloughs. There was water across the road circling the lower end of the runway, as well as flooding the gravel pit and barge landing area.

Wider weather episode

This spring an ice jam formed at Birch Tree Crossing, approximately 10 miles west (downstream) of Aniak. It held for a few days and resulted in high water and minor flooding around Aniak.

View location on OpenStreetMap → (61.6168, -159.5194)

Source: NOAA Storm Events Database, event_id 955279. Narrative written by the NWS forecast office that issued the report.