Video of the aftermath shows passengers' belongings all over the floor of the aircraft and what appears to be a drink cart tipped over.
Compass Airlines Flight 5763 took off from John Wayne Airport Wednesday morning heading for Seattle, but was forced to land in Reno.
The plane nose-dived twice during the flight, according to passenger Joe Justice.
"Crazy turbulence and injuries, but the Delta crew handled it perfectly, even the emergency landing," Justice tweeted.
Emergency crews rushed to the plane to assist at least three passengers and a flight attendant were injured on the flight, which carried a total of 59 passengers and four crew members.
The pilot called in the emergency in a recorded call: "We are an emergency aircraft, numerous injuries. We do not have the number of how many injuries. My understanding is that we have two flight attendants that may be incapacitated with several passengers."
There was a high-wind warning close to the path of the flight. At Hollywood Burbank Airport, some passengers said they can't help but think about the danger of turbulence with storms hitting Southern California.
"I've been on plenty of flights with turbulence and it is a frightening experience," said Pasadena resident Alfredo Gonzalez.
Passengers were loaded into another aircraft to continue their trip to Seattle. That flight landed at about 10 p.m.
Compass is a regional airline that operates flights on behalf of Delta and American Airlines.