Rescue crews searched Tuesday for a 25-year-old man who is missing after going swimming in the Potomac River south of Great Falls. Montgomery County Fire and Rescue said two people went swimming just south of Sandy Landing, but only one made it out of the water. WATCH HERE WATCH HERETeams from Fairfax, Loudoun and Montgomery counties rushed to the river Tuesday at about 2 p.m. Chopper4 images show their rescue boats. Nine boats went out to search for the missing man, fire officials said. Officials said the area where he went missing can get up to 50 feet deep.