Turbulence definitions!
Ok, after a good number of attempted definitions I thought it was about time for some official ones - straight out of the manuals.
Light turbulence: Slight changes in attitude or altitude or changes in IAS 5-15 kts
Light chop: Slight bumpiness without changes in attitude or altitude or IAS
Occupants may feel a slight strain against their seatbelts though no difficulty is encountered in walking.
Moderate Turbulence: Similar to light turbulence but of greater intensity, changes in attitude and or altitude occur, IAS fluctuates 16-25 kts, but the sircraft remains in postive control at all times.
Moderate chop: Turbulence that is similar to light chop but of greater intensity causing rapid bumps and jolts without appreciable changes in attitude or altitude.
occupants feel definite strain against seat belts or shoulder harness. Unsecured objects are dislodged. Food service and walking are difficult.
Severe turbulence: Causes large, abrupt changes in attitude or altitude. Aircraft may be momentarily out of control, IAS fluctuates by more than 25 kts.
Occupants are forced against seat belts or shoulder harnesses. Unsecured atems are tossed about. Food service and walking are impossible.
The continuity of turbulence is described as:
Occasional - less than 1/3rd of the time
Intermittent - 1/3 - 2/3rd of the time
Continuous- More than 2/3rd of the time.
Hope this helps some of the non pilots.
JK