WASHINGTON – A search that started Monday night on the Potomac River near Great Falls was expected to resume Tuesday after the man authorities were looking for had not been found.

Friends say sometime before 8 p.m., the 24-year-old went under after wading out too far into the river. Witnesses say he struggled against the water as he was pulled downstream.

Assistant Chief Scott Graham, a spokesman for the Montgomery County Fire and Rescue Service who is working with Fairfax County, tells WTOP rescue workers were dispatched around 8:30 p.m. The man they have been searching for is black, wore khaki pants and no shirt.

By 10 p.m., the search was called off for the night. Rescuers would resume the search at 8 a.m. Tuesday, according to Graham.

Three people have drowned in the Great Falls area of the Potomac River this summer, including an experienced kayaker.

“It is very treacherous underneath,” Graham says. “There are a lot of rocks, and the water is moving very quickly. It’s a very dangerous river although it may look calm and peaceful and serene at its surface.”

WTOP’s Nick Iannelli contributed to this report. Follow @NickWTOP and @WTOP on Twitter.