A woman from Cadet, Missouri, drowned in the Big River in Washington County on Tuesday, authorities said.
The victim is identified as 67-year-old Monica P. Boyer.
The Missouri Highway Patrol said Boyer was wading in the Big River near the Washington State Park boat access about 2:25 p.m. Tuesday when the water became too deep.
She slipped and fell and went underwater but didn't resurface, police said.
The Highway Patrol, which handles boating crashes and investigates drownings in the state, said at least 10 people have died on waterways across the state just in the first two weeks of June. The incidents were in eight counties.
At least six of the 10 deaths are classified as swimmers who drowned. One person died after a boat capsized; another died when a boat hit a rock. One man died after a boat swamped, and a child died after being hit by a propeller.