Investigators at Yosemite National Park said Thursday they are trying to identify the body of a man who was found Tuesday afternoon floating dead in Hetch Hetchy Reservoir.

Park officials say it may be a Los Gatos electrical engineer who friends say was swept off a bridge three weeks ago while hiking near the reservoir at Wapama Falls — a 1,400-foot waterfall that is roaring this year due to the melting of the heavy Sierra snow pack.

Friends say the man, Chris Mangan, 56, was an ardent hiker and mountain biker. He was on a day hike June 6 to Wapama Falls, located on the north side of Hetch Hetchy Reservoir, when he was walking across a wooden footbridge where raging rapids from melting snows were washing over the floorboards.

Mangan apparently slipped and went over the edge into the raging creek below, which flows to the reservoir.

“The walkway was like 2 feet underwater in some places,” said Gary Patterson, of San Jose, a friend of Mangan’s. “His friend walked across the bridge turned around to take a picture but Chris wasn’t there. He walked back and asked the people on the other side, ‘Did you see my friend?’ and they said, ‘No, he was with you.'”

Rangers found Mangan’s pack and hat in the area, which is marked by huge boulders and explosively powerful water. But they were unable to locate him, Patterson said.

“We did receive report of a missing person on June 6 in the Hetch Hetchy area,” Gediman said. “We instituted a search by land, helicopter and water on June 6, and we did not find anybody. A week or so later we scaled back the search.”

Nearly three weeks later, on Tuesday at 2:40 p.m., the Tuolumne County Coroner received a call reporting a deceased male at the reservoir near Wapama Falls, said Sgt. Andrea Benson of the Tuolumne County Sheriff’s Department.

Investigators have not yet identified the man, said Scott Gediman, a spokesman for Yosemite National Park, but are checking to see if it is Mangan.

There are several footbridges over the creek where the falls, which cascade down granite cliffs in three huge sections, flows. Signs at the bridges say “Dangerous High Water. Cross at Your Own Risk.”

Other hikers have been killed in previous years there, particularly after wet winters when the high-elevation snows are deep and cause rivers to run high and fast as they melt during the warm summer months.

Two years ago, Douglas Schlittner, a 66-year-old social worker from Huntington Beach, was found dead in Hetch Hetchy Reservoir after being swept off the bridge.

During that accident, which also happened in June, the falls were so loud and spray was so thick people crossing the bridge said they couldn’t hear each other speak or see more than a few feet ahead.

In 2011, Gregory Wayne Meyer and Richard Fox, both 53, of Los Angeles County, died while trying to cross a bridge at Wapama Falls. Meyer was trying to rescue Fox when both were swept away.

Hetch Hetchy Reservoir provides drinking water to 2.5 million people in four Bay Area counties: San Francisco, San Mateo, Santa Clara and Alameda.

With the July 4 weekend coming up, park officials are urging all Yosemite visitors to be aware of the increased danger.

“There’s a lot of water everywhere,” Gediman said. “There’s high water in all the rivers in the park. In higher elevations, there’s still snow, and there’s high, swift moving water. Please use extreme caution.”

Mangan’s friends said he was a friendly, outgoing person, who had worked for software companies and a cell tower company. He loved hiking, mountain biking and visited Yosemite four times in the past year.

“Chris was an adventurous guy. He climbed Mount Shasta in one day,” Patterson said. “We would bicycle together three times a week. He was very active and physically fit. He was the most physically fit 56-year-old I’ve ever seen.”

Mangan, a Los Gatos resident for about 25 years, was happiest in the rugged outdoors, Patterson said.

“He was an outdoorsman,” Patterson said. “He understood the risk. But he was an explorer. He said if I ever die, ‘I want my ashes spread at Yosemite.’ He loved that place.”