NWS forecasts up to 1.5 inches of rain in the Chena River basin

Up to 1.5 inches of moderate to heavy rain is expected across the Chena River basin over the next 48 hours, and the Chena and Little Chena rivers will rise with it. NWS Fairbanks issued the hydrologic outlook Thursday at 11:18 a.m. AKDT. It runs through 4 p.m. Friday.

"At this time flooding is not expected, but should the focus for heaviest rainfall shift further east with time, this could change," NWS Fairbanks said in the outlook.

The outlook covers 13 Interior forecast zones, from Fairbanks to the Koyukuk and Middle Yukon valleys. Forecasters attribute the rain to an atmospheric river bringing 1 to 2.5 inches region-wide, with average return intervals of 2 to 5 years and isolated pockets nearer 10 to 25 years. That return interval means rain this heavy is expected about that often. Rainfall rates are expected to decrease by Sunday afternoon across most of the area.

The Little Chena near Fairbanks has an action stage of 21 feet and a minor flood stage of 25 feet. It stood at 13.5 feet Thursday evening.

Heavy August rains in 1967 inundated roughly 95 percent of the city for about five days, damaging almost 6,000 homes and causing more than $170 million in damage, according to the borough's flood hazard profile. The Chena River Lakes Flood Control Project followed, and the U.S. Army Corps of Engineers has operated Moose Creek Dam since 1979 to hold the Chena through downtown to no more than 12,000 cubic feet per second.

The borough's own hazard profile notes the project controls only Chena River flows, and that many developed residential areas remain in approximate A zones, flood-prone ground with no calculated flood height, that the dam does not protect.

Residents can reach the borough Flood Plain Administrator at 907-459-1260 for floodplain boundary and permit information.