Running out of options, Whitson carved "Help" on a plastic water bottle and put a note inside," KSWB reported. "We are stuck here at the waterfall, get help please," Whitson wrote in his note.
The trio then created an "SOS" message from rocks, The Tribune reported.
At midnight, they were awakened by the sound of a California Highway Patrol helicopter, the newspaper reported. Two hikers had found the bottle about a half-mile downriver from the falls and contacted park rangers, KSBW reported.
"It was a big, huge sigh of relief," Whitson told The Tribune. "We were all dead asleep when they first came. They used the infrared to spot our campfire and said, 'This is search and rescue. You've been found.' I've never heard better words uttered in my life."
Whitson said he was amazed the bottle had done the trick.
"It blows me away how it all came perfectly together," Whitson told the Post. "What are the odds?"