A mother and her nine-year-old son lost in the rocky mountain forest of Sierra Nevada in the US state of California were rescued thanks to a trail of handwritten notes they left behind - after getting stranded for more than 24 hours.

A volunteer search and rescue team in Calaveras County was able to locate a mother and her son in a "labyrinth-like" forest area because of notes the mother had left on their trail. The team was forced to use a HAM radio to communicate with authorities upon locating the pair.