The Missouri Department of Transportation closed the Interstate 55 North exit to Carondelet and River City boulevards Thursday to allow for sandbagging efforts along the River des Peres.
Crews closed Exit 202A at 6 a.m. so that sandbaggers could do their work.
The highway exit ramp will not reopen until flood waters from the River des Peres recede, the agency said.
Drivers can use alternative routes off the interstate by taking the Bayless, Virginia or 4500 Broadway exits. The Loughborough exit is also currently closed due to water main work, but could open before the end of the day Friday.