Sporty's

Light Turbulence

1. Slight erratic changes in altitude or attitude.
2. Occupants may feel a slight strain against seat belts.
3. Unsecured items might move about slightly.
4. Light Chop: rhythmic bumpiness without appreciable changes in altitude or attitude.

Moderate Turbulence

1. Definite strains against seat belts.
2. Unsecured objects are dislodged.
3. Moderate Chop: rapid bumps or jolts without appreciable altitude or attitude changes.

Severe Turbulence

1. Large, abrupt changes in altitude and/or attitude.
2. Large airspeed variations.
3. Aircraft may be momentarily out of control.
4. Occupants are forced violently against seat belts.
5. Unsecured objects move freely about the cabin.

Extreme Turbulence

1. Aircraft is violently tossed about and is practically impossible to control.
2. May result in structural damage to the aircraft.
3. Conditions inside the aircraft can be worse than severe turbulence.