CALIFORNIA • Mr Curtis Whitson felt sick to his stomach when he realised that he, his girlfriend and his 13-year-old son were suddenly stranded on an isolated stretch of California's Arroyo Seco tributary.
They had reached the most difficult part of their four-day floating and camping trip in June, and they were trapped atop a raging, 12m waterfall. A rope that was supposed to be secured at the top of the chute - the only safe way down - was missing. There was no way to climb out of the gorge.
A sturdy rope had been attached to the slippery rock wall when Mr Whitson made the same journey seven years ago. At the time, he had carefully rappelled down the side of the waterfall in 15 minutes and continued his adventure.
Heavy spring rains had likely washed the rope away.
Friends knew they were in Arroyo Seco, but it could be several days before a search party was sent. There was no mobile service.
Mr Whitson looked at his lime-green Nalgene water bottle, and had an idea: He scratched "HELP!" on each side of the bottle and scribbled an SOS note on a piece of paper with the date, June 15, and their whereabouts - then tucked it inside. He tossed the bottle over the water chute and hoped somebody downstream would find it.
"We have done all we can do," Mr Whitson, 44, recalled telling his girlfriend Krystal Ramirez, 34, and son Hunter Whitson after he dropped the bottle over the roiling chute. "The only thing left to do now is wait." The trio made their way a few metres upstream to a strip of sand and crafted an SOS sign with rocks. Then they climbed into their sleeping bags.
Remarkably, they did not have to wait long. About midnight, they were awakened by a voice from a loudspeaker: "This is search and rescue - you have been found! Stay put and we'll be back to get you tomorrow morning."
The three of them later found out that about 400m downstream, two hikers had spotted the bright green bottle right away, read the note and hiked to the Arroyo Seco Campground to alert the manager, Ms Cindi Barbour, to call a search and rescue team.
"They told me they found the bottle in the narrows of the river," Ms Barbour said.
Using night vision goggles and infrared technology to detect heat from a campfire, the crew from a California Highway Patrol helicopter were able to spot the stranded trio. The next morning, a second helicopter crew arrived to lift each of them to safety.