Years ago while teaching a college geography class at UAA, I had a retired airline captain in the class comment on the hazards of turbulence while flying. He told a great story that has stuck with me to this day.

While flying the Anchorage-Seattle route, the plane encountered an unexpected area of clear air turbulence near Yakutat that caused a drop of several hundred feet. The seat sign was not illuminated and several passengers were injured. The plane had to make an emergency landing in Juneau and several passengers were transported to the local hospital.

A student asked the captain for further clarification on the incident and his comment was to keep your seat belt fastened even when the sign is off while you are in your seat. He then closed with "nuff said". I never forgot it and use his example each time I teach the class.