Kathi Jeanne Ludwig was with her husband in a group of at least eight people climbing the mountain at about 6 a.m. Sunday when a watermelon-size rock fell and struck her on the left side of her torso, according to the sheriff's department.
Ludwig was knocked back at least 15 feet and rolled several times on the frozen surface.
A U.S. Forest Service ranger who was in the area responded on foot to Ludwig's location, about 11,000 feet up the mountain, where CPR was being performed on her.
A California Highway Patrol helicopter crew hoisted her from the mountain and flew her to Mercy Medical Center Mt. Shasta where she was pronounced dead upon arrival, according to the sheriff's department.
The cause of Ludwig's death was determined to be cardiac arrest due to blunt force trauma to the upper torso.