Karen Klein walked for 30 hours through snow to get help for her stranded family.

It’s the survival story local police are calling a “Christmas miracle”.

US mother Karen Klein trekked for more than a day through snow-covered wilderness in a desperate attempt to get help for her stranded family, even eating twigs and drinking her own urine just to stay alive.

The Pennsylvania woman, her husband, Eric Klein, and their 1o-year-old son, Isaac, had been driving near the northern rim of the Grand Canyon in Utah, when their rental car became stuck in a ditch last Thursday.

Dressed in a beanie, parka and hiking boots, the community college biology professor and keen triathlete set out in search of help, reports local newspaper The Morning Call.

After discovering the nearest highway was closed due to heavy snowfall, she pressed on, ultimately walking nearly 42 kilometres over the course of 30 hours toward an entrance to the national park.

Karen's twin sister, Kristen Haase, told local news outlet WFMZ-TV the 46-year-old pulled a groin and suffered hallucinations on her journey, but was determined to push on.

"She would make a decision and she would stick to it and never give up. She would do it or she would die trying," Haase said.

“What kept her going, she says, is she didn’t want her mother to bury her daughter. She didn’t want her son to be without a mother.”

Karen ultimately stumbled across an empty cabin around dusk on Friday, smashing the window to gain access then passing out among blankets inside. It was there she was found six hours later by rescuers from the local Sheriff's Office who had tracked her through the forest, following a call from her husband.

Eric and Issac Klein were rescued earlier on Friday, having managed to climbed to a location with mobile phone reception when Karen failed to return.

The pair were taken to a local hospital suffering frostbite, while Karen was treated for exposure.

"She's a very tough woman," Coconino County Chief Deputy Jim Driscoll told WFMZ-TV. "Most people would not have survived the ordeal that she did."