Use the noun turbulence to describe instability or disturbance. If you’re on an airplane during a storm, turbulence is that horrible thing that is causing the plane (and your stomach) to bounce around.
The word turbulence can be used to refer to atmospheric instability, such as sudden, unpredictable air movements resulting from a storm, but the word has a broader meaning as well and you will often hear it used to describe any situation characterized by unrest and disorder. If your stocks are fluctuating wildly in price, that could be a result of turbulence in the stock market. If last year was filled with unpredictable change, you could describe it as a year of great turbulence.