Fasten your seatbelts, it's going to be a very bumpy flight.
That is the warning from Australia's crash investigators who say there has been an unprecedented increase in reports of turbulence affecting passenger jets.
Stuart Godley, the head of the Australian Transport Safety Bureau's aviation safety research team, said he had seen a doubling of turbulence and windshear incidents in the last three months of last year.
"Some of those events are affecting the safety of those in the cabin," Dr Godley said.
The report found that from October to December last year, the number of turbulence and windshear incidents was significantly above the five-year average. It was double the number in the previous three months.
"Because they're weather-related, these events are cyclical," Dr Godley said.
"We're used to seeing more of them in the summer, but this increase is unprecedented."
Turbulence is the leading cause of injuries to passengers and crew.
"When air masses with different speeds, direction or temperatures meet each other, turbulence is likely to occur," the ATSB report said.
The increase has prompted the ATSB to produce a booklet to help passengers understand turbulence and prevent injuries.
In the five years to 2013, there were 677 turbulence incidents on flights reported to the ATSB, with 197 minor injuries and two serious injuries.
The US Federal Aviation Administration estimates the cost of turbulence incidents to the worldwide industry is more than $US100 million a year.