ATC still does a good job of warning aircraft approaching (from either direction and at the same general altitude) once an aircraft initially reports it. While there are some forecast tools that can pick out possible areas it doesn't always occur. If your the first to encounter theres not a whole lot you can do other than, like many said, keep your seatbelt on even loosely. I might add that the flight path was across the rocky mountains into the Northern plains at the same time that an anomalous cold air system for August is working its way southward. A lot of downsloping flow from this system along the East side of the mountains can create ripples upwards through the atmosphere. This Northern plains along with the desert SW have a higher frequency of clear air turbulence than other areas around the country. Sail plans take advantage of this phenomena and can fly from southern Utah all the way up to the Grand Tetons and back riding the mountain "wave" like a surfer in the atmosphere. Whether Climate Change is exasperating this specific phenomena would be difficult, not impossible, but difficult to study. Like rogue waves in the ocean, we usually only know about them when something encounters them.
And just another point to simplify it for people, these incidents get magnified because they are occurring in an aircraft at 30 thousand ft while your having cocktails. The forces and altitude changes are about the same as you would experience on your average roller coaster. Imagine being on that coaster with no lap bar trying to have a beer 
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