Two climbers had to spend the night stranded in sub-zero temperatures on the North Shore Mountains after venturing into an area that's closed to the public.

One of the climbers fell while rappelling down from Spindle Peak on Monday and ended up sliding dozens of metres down an icy mountainside. She suffered a number of suspected breaks and fractures that made it impossible to get out on her own.

Fortunately, her partner, Serguei Okountsev, was able to call for help using an emergency beacon and satellite phone they wisely were carrying.

"I thought she was dead before I reached her," Okountsev said. "It's pretty bad. I think 99 per cent of people wouldn't survive."

Okountsev said you can tell the seriousness of the fall by the state of his partner's destroyed helmet.

"It's damaged from all possible sides; it's just a piece of junk now," he said. "Hard to believe that it took so much abuse."

Volunteers from North Shore Rescue hiked for about six hours in the dark to reach the pair and provide comfort overnight, and didn't arrive at their location until around 3:15 a.m.

On Tuesday morning, both of the climbers were longlined off the mountain using a helicopter.

Their rescue capped off an already busy Family Day that saw volunteers conducting back-to-back missions on the North Shore. Search manager Peter Haigh said some of the dedicated team members worked all day before heading out to spend the night with the climbers.

"It was a long walk for them," he said.

Frustratingly, it appears the climbers, who were preparing for an expedition on Denali in the spring, never should have been out in that area to begin with.

"It's an area that's actually closed to the public at the moment, so they really shouldn't have been back there – but that doesn't seem to stop people," Haigh said.

After being carried off the mountain, Okountsev told reporters he didn't realize the area was closed when they were heading in on Monday.

He also offered effusive thanks to the search members who made sure they were able to come home safe.

"They stayed with us through the night. These are volunteers, unpaid volunteers. I don't know how much it takes to do such commitment," Okountsev said. "It's amazing. These guys are amazing"

With files from CTV Vancouver's Nafeesa Karim