This summer, Curtis Whitson, his girlfriend, and 13-year-old son were hiking in Central California when they became stranded in a canyon near a waterfall with no way out. According to KSBW, "Whitson said he had rope to rappel down, but the river was running too swift and deep due to spring runoff. Backtracking was also not an option." Whitson found a green plastic water bottle, carved "HELP" in the side, put in a note, and tossed it over the waterfall. From CNN:
Some time after midnight the trio was awakened by the sound of a California Highway Patrol helicopter overhead.
"This is Search and Rescue. You have been found," someone said over the loudspeaker.
Whitson said he was told two men found the bottle with the family's note, floated down to the trailhead, then hiked a couple of miles and reached the campground where they alerted the camp host.
That host told Whitson about the hikers, but added the two left before the rescue without giving their names.