A San Francisco father of four who left his family a week after their car got stuck on a snowy, remote road in Oregon made a tragic miscalculation of the distance he had to cover to find help.

Oregon police said Thursday that James Kim, whose body was found Wednesday in the mountains of southern Oregon, died of exposure and hypothermia. The discovery brought an end to what authorities called an extraordinary effort to stay alive.

Kim was a senior editor for the technology media company CNET Networks Inc. He and his family had been missing since Nov. 25. They were heading home to San Francisco after a family vacation in the Pacific Northwest.

Kim's wife, Kati, 30, told officers that the couple made a wrong turn and became stuck in the snow. They used their car heater until they ran out of gas, then burned tires to stay warm and attract attention. They tried to put wood underneath their car to keep it dry to burn. With only a few jars of baby food and limited supplies, Kati Kim nursed her daughters Penelope, 4, and Sabine, 7 months.

The family burned tires in an attempt to create signal flares, authorities said. At night, they huddled together for warmth.

Oregon State Police Lt. Gregg Hastings said Thursday that Kim left the car shortly before 8 a.m. last Saturday to get help. Right before he left, he built a fire for the family, and he and Kati studied an Oregon map to determine which route he should take.

"They thought the Hanna police was just about four miles away, when in reality, it was probably more like 15 miles away," Hastings said. "James thought he could reach it in a couple of hours ... he was trying to get to a road, to flag down some help."

Kim's family told authorities that when he left, he was wearing tennis shoes, pants and a heavy coat, but no hat. His family said he had some outdoor experience, and authorities said he was carrying two lighters.

Despite his plan, Kim never came back.

Hastings said Kim traveled about 10 miles from the car before he died and said there was no way he could have reached the car directly from where he was found. He was discovered Wednesday lying on his back in the Big Windy Creek near the Rogue River.

He was carrying a backpack that held identification, among other items.

Searchers had been following his footprints in the snow and searching by helicopter since his wife and two young daughters were rescued Monday. The key to finding Kati Kim and the two children, police said, was a "ping" from one of the family's cell phones that helped narrow down their location.

During the hunt for James Kim, searchers also found pieces of his clothing, which they believed he left and arranged to give searchers clues to his whereabouts in Oregon's Coast Range.

Before rescue crews could drop packages with clothing, emergency gear and provisions, a search helicopter spotted Kim's body at the foot of the Big Windy Creek drainage, a half-mile from the Rogue River, where ground crews and helicopters had been searching for days.

"He was very motivated," said a tearful Undersheriff Brian Anderson. "We were having trouble in there. He traveled a long distance."

CNET's CEO said the company will provide grief counseling for employees. Executives are also trying to determine what type of memorial to provide in Kim's honor.

The Associated Press contributed to this report.