Extraordinary circumstances is a legal term for any situation or event that’s outside of the airline’s control. Common examples that cause flight delays include bad weather conditions, such as storms, snow, or heavy fog, or disruptions caused by air traffic control or airport staff going on strike. Less common occurrences — including natural disasters like earthquakes or volcanic eruptions, terrorist incidents, or even other unruly passengers — also count as extraordinary circumstances. However, each situation must be considered on a case-by-case basis. For example, while a heavy snowstorm is often considered an extraordinary circumstance, at many airports snow is common in winter, and airlines should be prepared for it. If your plane was delayed by snow, while others made the necessary preparations to take off on time, we would argue that bad weather doesn’t count as an extraordinary circumstance in this case.