The couple was driving home to Helendale Tuesday afternoon when they detoured around a closed road on National Trails Highway and got stuck in the sand.
The couple started walking. George Meisenhelder, 78, collapsed a half-mile into their trek.
Guadalupe continued to walk but fell down a 35-foot embankment into a riverbed and suffered broken bones.
A hiker found the husband, who was unconscious and near death.
Rescuers giving him medical help noticed he began mumbling about his wife. She was found conscious, but seriously injured.
Guadalupe was air lifted to the hospital, where she later died from her injuries. Her husband was treated at the same hospital and released.
A fire department spokesperson cautioned desert travelers never to leave main roadways, and always carry water and a cell phone.