The community of Nunam Iqua, photographed in 2009. (Photo courtesy of Department of Commerce, Community and Economic Development; Division of Community and Regional Affairs’ Community Photo Library)

Bryan Simon and his team of search and rescue volunteers left Scammon Bay around 10:30 Monday morning. Snowmaching along the Black River, Simon scanned the white landscape for any minute detail, like he’s been trained to do. A hundred yards away, on the highest snowdrift, he saw something he said was suspicious.

“It didn’t look like anything. And then as I got kinda closer, I seen movement,” Simon said. “I couldn’t believe my eyes.”

Related: Nunam Iqua boys who were lost in the snow have reunited with family

Simon was 18 miles south of Nunam Iqua, a small village near mouth of the Yukon River along the Bering Sea in western Alaska. He was looking for four children — Christopher Johnson, age 14, Frank Johnson, age 8, Ethan Camille, age 7, and Trey Camille, age 2 — who’d left on a snowmachine Sunday afternoon. They’d been heading for the dump near the community, but a blinding snowstorm had come in, and the children disappeared. It had been more than 24 hours since they were last seen.

Simon and others from neighboring villages had been searching a vast, uninhabited stretch of lakes and tundra. The temperatures since the children vanished had been just below freezing, with gusting wind and snow, according to weather.com. With windchill, it had been just above 0 degrees.

Simon signaled the rest of his four-man team. They approached. There was something alive in the snow.

“Right away, I look for that little infant. When I got kinda close to them I thought I only seen one kid,” Simon said.

That’s because Simon saw just one mass, all four children bundled together. They had dug a hole in the snow, about a foot deep, three feet in diameter.

“The infant was in there,” Simon said. “And the boy laid over the infant, and on his left side, a little older boy covering the draft. And the seven-year-old was laying right above them like he was blocking the wind.”

“They were protecting the baby,” said Herschel Sundown, Simon’s teammate.

Sundown, a former health aide, approached the scene and started assessing the children. The oldest had on a pair of sweatpants that had become soaked. One of the other boys was missing gloves.

Related: Children who went missing in a storm in Nunam Iqua found alive but severely hypothermic

“I won’t get in exact detail, out of respect for the boys, cause from what I hear, they’re still in some critical condition, I’ll just say it didn’t look good,” Sundown said.

The rescue team immediately got to work, slowly warming up the boys’ bodies. They removed the boys’ wet clothes and wrapped them in parkas the search members had been wearing.

“One of the guys put a canvas tarp over us and we huddled with all of them to try to give out some heat to them,” Sundown said.

Then he started peppering the boys with questions.

“What they can and cannot feel,” Sundown said. “If they’re able to feel us touching them.”

He did not say what the boys responses were.

The search team’s leader radioed the Coast Guard.

“And I wanna say 15 minutes or less, we were able to hear a helicopter coming,” Sundown said.

The mission may have ended for the searchers, but for the boys, the battle is not over. The Coast Guard transported the children to Bethel, where three of them were treated for severe hypothermia at the Yukon Kuskokwim Health Corporation. Ethan, the 7-year-old, was transported to Anchorage. He was listed as a patient at Alaska Native Medical Center on Wednesday.

Still, the boys already defied the odds. For one, Sundown says their rescue was lucky. They were in an area other searchers had passed through multiple times without seeing the children.

“And it’s just the angle that we came in that we were able to spot them,” Sundown said. “We didn’t think we would find them, but we did.”

Plus, they’ve survived over 24 hours outside, through the night, forming a human shelter for their two-year old brother to stay warm.

“In all honesty, I don’t know how they survived,” Sundown said. “The will to survive in these boys is amazing. I have never seen anything like that.”

In addition to Scammon Bay, local groups from Nunam Iqua, Alakanuk, Emmonak, and Kotlik also participated in the search. Hooper Bay and Chevak were available on standby while the U.S. Coast Guard and National Guard provided assistance from the air. Alaska State Troopers coordinated the state-wide effort that brought the four missing boys from Nunam Iqua in from the cold.

Editor Julia O’Malley in Anchorage contributed reporting to this story.