An elderly woman is dead and her husband severely burned after they wandered from their car in eastern San Bernardino County on a day when area temperatures reached 116 degrees.

The couple from Oracle, Ariz., was driving Monday near the California side of the Colorado River when Virgil Sanders, 90, stopped their car, got out and walked away, San Bernardino County Sheriff's Sgt. Tim Smith said.

Authorities don't know why he did, but 77-year-old Joyce Sanders took off in search of her husband.

A passerby Monday evening found them 50 yards from their car at the bottom of a hillside.

Joyce Sanders was pronounced dead at the scene. Authorities said Wednesday that her husband was hospitalized in extremely critical condition with second- and third-degree burns from the sun and lying on the ground.

An autopsy is scheduled for Joyce Sanders.