YOSEMITE NATIONAL PARK (CBS13) – With temperatures dropping, an urgent search is underway for an Oakland man reported missing in Yosemite National Park.

Thirty-six-year-old Alan chow was last seen at the entrance to the Hetch Hetchy Reservoir and had a permit to go backpacking in the area.

Search and rescue teams were deployed yesterday to search hiking trails and surrounding areas for Chow, say authorities.

Chow has reportedly taken hiking trips before. But he was hiking alone.

Chow’s friends and family are concerned about below zero temperatures in the park.