Yosemite spokeswoman Kari Cobb says the family of the pilot, who was the only person aboard, reported him missing Tuesday morning.
The family says he departed Santa Barbara at about 12:30 p.m. Monday.
Cobb says despite assistance from the Air Force and state emergency services, only minimal searching was possible Tuesday because of tough weather conditions.
The plane went off the radar as it flew over the North Dome area of the park, and the nearest road is closed for the season, adding another challenge to the search.
Cobb says the pilot is from the Santa Barbara area. His name has not been released.
The Associated Press contributed to this report.