SPANISH FORK, Utah — An 18-month-old girl whose mother crashed their car into a Utah river survived hanging upside down in a car seat for some 14 hours in freezing temperatures before a fisherman found her, authorities said.

The mother, 25-year-old Lynn Groesbeck of Springville, was found dead in the car, and her daughter Lily Groesbeck was in critical but stable condition at a Salt Lake City hospital, police said Sunday.

“She is doing remarkably well considering the circumstance. The doctors have been hopeful so far,” the mother’s sister, Jill Sanderson, told KSL-TV of Salt Lake City on Sunday. “We would like to express our appreciation to the Spanish Fork rescue team for saving the baby’s life.”

The fisherman discovered the car on its top in the Spanish Fork River about 12:30 p.m. Saturday in Spanish Fork, about 50 miles south of Salt Lake City, police Lt. Matt Johnson said.