HELENA, Mont. A Sunwing Airlines flight en route to Mexico from Edmonton made an emergency landing in Montana on Sunday morning after hitting severe turbulence that injured a flight attendant.

Flight 559 was early on in the flight when it encountered what was described as about 45 seconds of moderate turbulence followed by about 45 seconds of severe turbulence, said Janine Chapman, a spokesperson for the Toronto-based airline.

The passengers were wearing their seatbelts at the time but two flight attendants were walking in the cabin when the turbulence occurred, Chapman said.

Both fell but neither needed hospitalization.

The flight landed in Helena as it is customary to do a maintenance check when an aircraft encounters heavy turbulence, Chapman said.

Sunwing brought another plane from Toronto and the passengers left Sunday evening for Puerto Vallarta.