A flight from Edmonton, Alberta to Puerto Vallarta, Mexico operated by Canadian carrier Sunwing Airlines had to divert to Helena, Montana early this morning due to severe turbulence that injured a flight attendant.

Frequent fliers know the routine: seat up, bags stowed, phones in airplane mode, keep your seat belts fastened at all times as we can never predict rough air. When flight attendants go over their safety speech at the beginning of a flight, they're not doing it because they have to. The information is presented to help keep you safe. Rough air — polite airline-speak for turbulence — really can be unpredictable and dangerous if you're not strapped in when it happens.