Several passengers were seriously injured when a Hawaiian Airlines flight from Phoenix to Honolulu hit severe turbulence, the airline and a local emergency-management agency said Sunday. 

Hawaiian Airlines Flight 35 encountered the turbulence shortly before it arrived in Honolulu and landed safely at roughly 10:50 a.m. local time, the airline said. 

Some people aboard the flight were taken to The Queen’s Medical Center in Honolulu.

Photo: Audrey McAvoy/Associated Press

Honolulu Emergency Medical Services said paramedics and emergency medical technicians treated 36 patients at the airport after the flight landed. Of those, it said 20 were transported to emergency rooms, with 11 patients in serious condition and nine in stable condition, the agency said. Injuries included head lacerations, bruises and loss of consciousness, it said.

The airline said in a written statement that it is continuing to support the 17 passengers and three crew members who were injured. The airline said it is conducting an investigation of the plane before returning it to service.

Turbulence is common. It can occur unexpectedly and can be caused by atmospheric pressure, jet streams, air around mountains, storms and cold or warm weather fronts. 

Severe injuries are more rare, and flights where more than one or two people are hurt badly are uncommon, according to federal figures. 

The flight, on an Airbus A330, reported severe turbulence with injuries to crew and passengers at roughly 10:35 a.m. Hawaii Standard Time, a spokesman for the Federal Aviation Administration said in a written statement. The agency said that it would investigate the incident. 

The National Transportation Safety Board said Monday that it is also opening an investigation into the incident.

Write to Alison Sider at alison.sider@wsj.com