Two 13-year-old Boys Scouts and two adult leaders were airlifted out of Mount Baker Monday after getting separated from their troop on Sunday. U.S. Customs and Border Patrol released video of the rescue Tuesday.

The four hikers were first reported overdue around 4 p.m. Sunday, last seen near Coleman Glacier. The Whatcom County Sheriff’s Office says the group spent the night in a cave for shelter, where temperatures dipped to as low as 17 degrees overnight.

A search and rescue team (SAR) from Naval Air Station Whidbey located the missing hikers around 9:30 a.m. Monday near "North Dome." They were initially flown to St. Joseph's for evaluation, then taken to Harborview. The boys are listed in serious condition in intensive care and the troop leaders are listed in satisfactory condition.

WATCH: Boy Scouts rescued off Mount Baker

SAR mission commander Lt. Chris Pitcher said, "Due to the conditions this was definitely one of the most challenging rescues I've been on. The fog bank on the northwest side was creeping in." The Navy says wind, high altitude, and the weight of the crew and rescued climbers were additional challenges.

"It took us utilizing every member of our crew at the maximum limitations of our helicopter," said copilot Lt. Matt Schwab.

The SAR crew worked in conjunction with a U.S. Customs air unit to help identify the stranded climbers. Lt. Pitcher said, "We were grateful to have the U.S. Customs air unit aiding in the rescue."

NAS Whidbey Island SAR, has now conducted nine rescues and four searches for 13 total missions throughout Washington State this year.