Having driven this section of road many times for spring break, and not being there to see it, this is exactly what happened...;)
The far left lane was going 85mph while the right lane was going 75 mph. This person towing the trailer was going a resonable 65 mph in the center lane to avoid merging and exiting traffic. Someone going 90 mph decided they needed to pass on the right but there was unbelievably an even slower moving vehicle in the right lane. So to get back left before hitting said slow vehicle they cut off the SUV towing the trailer causing them to take evasive action but in the process lost control and flipped the trailer.