CALIFORNIA (CNN) — A California family wants to thank two hikers who they say saved their lives.

Curtis Whitson, his girlfriend, and his 13-year-old son got stuck when they reached a river after two days of hiking in central California.

They intended to float down that river on inner tubes, but the water was too high.

It’s also in a 40 foot deep canyon… And the ropes typically fastened to rocks that allow hikers to rappel down were missing.

Whitson heard voices on the other side of a waterfall… So he carved “help” on a reusable water bottle he found, put a note inside, and threw it over the waterfall.

Two hikers on the other side found that bottle, and alerted authorities.

The family wants to thank those hikers… But they never left their names with officials.