Napaimute Floods During Spring Break-up

Observation by Mark Leary:

The flooding we are experiencing is a direct result of climate change and the late freeze up in 2019. The water was extremely high and the ice from Chuathbulak to Napaimute (20 miles) kept stopping and moving - getting rougher and thicker each time.

This area was impassable even by snow machine until we plowed a road through it in early February. It took us 14 hours to push through it with a dozer, plow truck, and grader.

The cold winter and deep snow compounded it. Our ice radar was showing ice up to 7’ thick.

Shared with Erica Lujan via email on 5-2-2020

Comments from LEO Editors:

This observation as been shared with the National Weather Service, Alaska Pacific River Forecast Center and the Emergency Preparedness program at ANTHC.

Crane Johnson, hydrologist with the Alaska Pacific River Forecast Center, presented a forecast of spring 2020 break-up conditions in the April LEO Network webinar. Crane discussed snowpack and spring weather as two main contributors to ice thickness and break-up conditions. A cold winter contributed to thicker river ice than has been observed for a number of years, though in some places, freeze up was late. This year, warm May temperatures are expected to rapidly melt the above-average snowpack in much of the Interior. As snowmelt runs in to still-stable and relatively thick river ice, the risk of ice jams and flooding increases for many river communities.

On April 27th, the Alaska State Emergency Operations Center (SEOC) reported that the Yukon and Kuskokwim rivers were beginning to break up. On April 28th, a special weather statement warned that warm air temperatures and rapid snow melt were causing water levels to rise, initiating breakup. Thick river ice was leading to ice jams and flooding in the Interior. On Friday, May 1st, a flood warning was issued for the Kuskokwim river from Napaimute to Kalskag, and extended until the night of May 4th.