Update (6:15 a.m. Monday): The National Weather Service in Tulsa extended Sunday's flood warning for the Illinois River near Tahlequah until late Tuesday night.
The warning was extended for the river near Watts and at Chewey until about 1 a.m. and 7 a.m., respectively.
Overnight Monday, the river's stage was 23.29 feet, according to the warning. Flood stage is 13 feet.
At 23 feet, "very severe" flooding occurs from the Arkansas border to Fidler's Bend.
The building at River Valley Raceway is flooded to a depth of a couple of feet, and numerous cabins in the Fidler's Bend area are flooded to a depth of several feet, the warning states.
"Major flooding is occurring, but the river is falling," the warning states.
The National Weather Service in Tulsa issued a flood warning for parts of the Illinois River in eastern Oklahoma after heavy rainfall Saturday and Sunday.
Moderate to major flooding is forecast along the river in Adair, Cherokee, and Delaware counties beginning as soon as Sunday afternoon, according to the weather service.
The river is forecast to crest at 24 feet at the Watts-U.S. 59 Bridge at 7 a.m. Monday, with a 24-foot crest at the Chewey-Hampton Bridge by 1 p.m. Monday, according to a news release from the Grand River Dam Authority. The river will reportedly crest in Tahlequah at 22 feet about 7 p.m. Monday.
"At present, water levels are forecast to be at levels similar to the Flood Event of October 1986, which was approximately 5-6 feet lesser than those of the two most-recent Major Flood Events occurring in December 2015 and April 2017," the news release stated.
A forecast from the National Weather Service stated at 25 feet, "very severe flooding" occurs from the Arkansas state line to Fidler's Bend, including at the River Valley Raceway and at cabins in the Fidler's Bend area.