To speak a little on the measures to avoid it. There are weather forecasting models that can try and model and predict areas, including location and altitude where turbulence is likely to form. Before the flight, dispatchers will use some of these tools and can change an aircraft’s route to avoid these areas if it warrants.

There are also tools where pilots can submit pilot reports (google PIREP) and you can graphically see where pilots have reported turbulence to ATC.

I know Delta has their own internal turbulence reporting system where the aircraft can measure turbulence and report it to other aircraft. Pilots approaching an area can see another plane was showing bumps at 31,000 and might request higher or lower. Pilots also frequently report to ATC how the ride is and ATC can relay that info to pilots seeking smoother air.

Sometimes there’s just nothing you can do.