Alyof Krost became separated from his hiking party Tuesday around 5:45 p.m.
Krost, who is visiting from Germany, is known to be an experienced hiker and hunter. He, however, doesn't have any equipment with him.
The hiker was last seen wearing a light blue, long sleeve shirt with dark blue denim jeans and a pair of lightweight hiking shoes.
Search and rescue crews were looking for Krost from the air and on the ground. Ground crews were expected to suspend the search overnight, but a helicopter with infrared cameras was to be deployed during the night.
A command post was set up at the Arrowhead Fish & Game Conservation Club on Highway 173.
Anyone with information regarding Krost's whereabouts was urged to contact the Twin Peaks Sheriff's Station at (909) 336-0600 or San Bernardino County Sheriff's dispatch at (909) 387-8313.
