YOSEMITE (CBS SF) — Authorities on Wednesday are searching for an Oakland man who has been reported missing in Yosemite National Park.

Alan Chow was last seen on his way to the Hetch Hetchy Trail on Saturday.

Search and rescue teams were deployed Tuesday to search hiking trails and surrounding areas.

Chow has taken hiking trips on his own before and this was planned as a solo hike.

Friends and family are concerned about below zero temperatures in Yosemite.

Chow is described as a 36-year-old Asian man standing about 5 feet 8 inches tall and weighing 140 pounds. He was last seen wearing a blue backpack with grey straps.