A trio of hikers — an Army veteran, his hiking friend and a service dog — was stranded overnight Sunday amid freezing temperatures and blizzard-like conditions in the San Bernardino Mountains on a mission to plant an American flag at the summit, and somehow survived.

"We both knew we were going to die if we stayed up there," one of the hikers, Tiffany Finney, said from her hospital bed after being rescued.

Authorities said Finney was half an hour from death when they found her on the mountainside. She was overcome by frostbite and may need to have fingers and toes amputated.

Finney recalled the harrowing encounter that nearly took her life and the life of Army veteran Kenny Pasten, whose service dog, Rexitron, accompanied them on the day hike near Big Bear.

The trek started off as any other, but with one important goal: to place an American flag at the San Gorgonio summit. As the three made their way up the 11,000-foot mountain, the weather quickly changed.

"It was like a blizzard," Finney said. "You just got smacked in the face with snow, really hard."

They tried to build a snow shelter to keep warm by using a sleeping bag and the American flag. As the sun went down, the temperature continued to plummet and the trio couldn't take it anymore. Finney and Pasten were overcome by frostbite.

"We couldn't feel our fingers our toes," Finney said.

They wandered down the mountain for hours in the darkness, and somehow survived the brutal night. By morning, they finally found a spot with cellphone reception and called for help. Rescuers were able to find them and land a chopper amid dangerous wind conditions.

Finney said she was near death, with a core body temperature of 85 degrees.

"I saw her basically crawling on her hands and knees heading toward what I can only thing was the sound of the aircraft," said Sgt. Daniel Futscher of the San Bernardino County Sheriff's Department.

Authorities said they were shocked by the hikers' conditions.

"That is probably most severe case of hypothermia I've seen in a conscious victim," said Eric Sherwin of the San Bernardino County Fire Department's air rescue team, describing Finney's injuries. "She had about a half-hour left before we would have seen a fatal injury to the hiker."

Rexitron was OK, but Pasten suffered frostbite and showed signs of kidney failure. He was recovering Tuesday. Finney suffered severe frostbite all over her body, with the worst of it affecting her hands and feet.

"My shoes were so frozen to my feet that they had to pour boiling water on it," Finney said. "I don't care if I lose toes or fingers. I'm alive."

Community members are raising money through GoFundMe to help cover Finney's medical expenses.