Four young people have drowned in the Potomac River near Great Falls this summer, prompting four law enforcement and rescue agencies to issue a joint warning: stay out of the water entirely.

Montgomery County Police, Montgomery County Fire and Rescue Service, Maryland Natural Resources Police and the U.S. Park Police released the warning Thursday, Aug. 13, urging residents to avoid the river regardless of how calm it appears from shore, according to Montgomery Community Media.

"4 young people drowned this summer," Pete Piringer, public information officer for Montgomery County Fire and Rescue Service, said in a post about the warning.

The death toll rose from three, as we reported July 30, when the body of a 25-year-old man was recovered near Sandy Landing south of Great Falls. The identity and circumstances of the fourth victim have not been released.

Officials said the river is choppy and unpredictable beneath the surface, with sudden drop-offs that can turn a casual dip into a life-threatening situation within seconds. The stretch south of Great Falls can reach 50 feet deep.

What's allowed and what's not

Swimming is prohibited anywhere along the Potomac in the Great Falls area. Wading in the shallows is also off-limits. The only permitted activities on the water are boating and paddleboarding while staying close to shore.

Warning signs in multiple languages have been posted along the riverbanks as part of the multi-agency safety effort.

'People will still do it'

The pattern has frustrated first responders all summer. MCFRS Assistant Chief Daniel Ogren told Bethesda Magazine on July 29, during a multi-day search for the third victim, "It's dangerous to do it, but people will still do it."

Montgomery County Police said on X on Wednesday, Aug. 12, that every year people underestimate the power of the Potomac River at Great Falls.

What to do if you see someone in distress

Officials urge bystanders to call 911 immediately rather than attempting a water rescue themselves.