A cyclist has been praised for having “stepped in decisively” and rescuing four members of a family who nearly drowned in the Ruhr River in Germany during a waterside barbecue that nearly ended in tragedy.

The family of eight had set themselves up on the riverbank in the western city of Bochum, the local fire brigade reported, but the gathering took a panicked turn when one woman got too close to the water’s edge and toppled down into the current, police told local media.

Another woman who waded in to try to help her also lost control in the water.

Two more relatives rushed in in an effort to pull the others to safety. All four, who were unable to swim, ended up in jeopardy, unable to pull themselves on to dry land despite the relative shallowness of the water at that point in the river.

The cyclist, who is also a doctor, rode past and immediately recognised what was happening in the strong current and “stepped in decisively” to help the three women and a man, a fire brigade spokesperson said.

She managed to drag each of the victims out of the water to safety and administered first aid to a woman who was already unconscious. All survived.

A family member alerted the authorities.

Emergency services workers who arrived soon after the cyclist’s intervention transported a woman who needed immediate medical attention to hospital. The other three victims had only minor injuries. The German Life Saving Association (DLRG), a voluntary water rescue organisation, dispatched a boat to the site.

The other family members required assistance during the nearly two-hour rescue operation due to the traumatic nature of the narrowly averted tragedy.

“The relatives were deeply shaken by the incident after seeing their family members in mortal danger,” the fire brigade spokesperson said.

Police have launched an investigation into the exact cause of the incident.

The local DLRG chapter and the fire brigade issued a renewed warning on the risks of rivers and streams, particularly for non-swimmers.

“Currents, steep banks and cold water temperatures can put even experienced people in danger,” the fire brigade said in a statement, noting that swimming in the Ruhr is considered life threatening due to its unpredictable currents.

Those wishing to take a dip in natural waters should stick exclusively to designated and supervised bathing areas, it added.

Last month, a 14-year-old boy drowned in the Ruhr in Essen, about 24 miles west of Bochum. The recent heatwave in parts of Europe led to a spate of drownings and other water-related deaths in the UK and France.

The Royal Life Saving Society UK has issued a plea for members of the public to “stop and think” before getting into the water. “Warmer weather unfortunately sees an increase in accidental drownings,” it said.