LAKE OF THE OZARKS - UPDATE 6/12: The National Weather Service issued a flash flood warning for some areas along the Osage River after Ameren Missouri opened the Bagnell Dam floodgates.
The weather service said the flood gates opened Wednesday morning and issued the warning through 8:15 p.m. Wednesday for the Osage River in central Miller County.
Ameren had said Tuesday night that the floodgates had already opened.
A flood warning was also issued for the Osage River near St. Thomas. The weather service said heavy rainfall could push river levels significantly higher in that area.
ORIGINAL: The Bagnell Dam floodgates opened Tuesday evening, prompting an alert to property owners from officials in at least one mid-Missouri county.
Ameren Missouri said Tuesday it had opened the gates, and they might remain open for several weeks.
Warren Witt, the utility's hydropower director, said in a news release that people at the Lake of the Ozarks and along the Osage River should be ready for fluctuating water levels.
The Osage County Emergency Operations Center, which tracks Bagnell Dam releases and their effect on Osage River levels, warned property owners in a Facebook post Tuesday that Ameren, which owns and operates the dam, would open the gates at about 7 p.m.
The dam was releasing about 40,000 cubic feet of water per second Tuesday evening, but that level could rise much higher. The releases were made to accommodate water flowing into the Lake of the Ozarks from the Truman reservoir. Recent rains have pushed the reservoir, operated by the Army Corps of Engineers, to near the limits of its capacity, according to Corps officials.
Floodwaters on the Missouri and its tributaries have been receding this week, though they remained well above flood stage in some areas Tuesday. Part of the Osage River was reopened to recreational traffic Monday, signaling that water levels had fallen to a level deemed safe by state officials.
Ameren and the Corps of Engineers say it's possible the flow will continue to increase throughout the week up to the max 80,000 cubic feet per second. That decision will depend on Missouri River levels at Hermann and Osage River flows at St. Thomas as well as rain forecasts.