A 21-year-old man died Friday evening near the Green River Gorge Bridge while helping his girlfriend reach shore, the King County Sheriff’s Office has reported.

The Sheriff’s Office was alerted around 3:30 p.m. that day that the man had gone missing while swimming near the bridge. Deputies and searchers had recovered his body by about 5:20 p.m., sheriff’s office spokesperson Sgt. Tim Meyer said.

The man’s girlfriend survived and was picked up by rescuers.

The Sheriff’s Office does not release the names or causes and manner of death of cases like these, Meyer said, and he deferred those questions to the King County Medical Examiner, which had not released that information by press time Monday.

Despite the rising temperatures and sunshine of spring, lakes and rivers remain extraordinarily cold this time of year and can sap swimmer’s energy rapidly.

“Air temperature and water temperature are not the same,” Meyer said. “And in our swift rivers like this, they’re coming from the mountain, from snowmelt. They’re going to be cold. It’s easy to think that warm air is going to mean warm water, and that’s not the case.”

Even a shallow stretch of river can be very hazardous, Meyer said, since they hide dangers like rocks, eddying water, and tree branches that can snag swimmers. In many cases, a shallow river can be more dangerous than a lake, Meyer said.

“Rivers are NOT SAFE at this time of year! They run high and swift even for the best swimmers,” the Enumclaw Fire Department said in a Facebook post Saturday in regards to the man’s death.