Trailer crash on mountain road.

It looks to me that maybe there was a combination of too long of a TT for the tow vehicle and sway induced while passing the truck. Just because the tow vehicles is rated to pull a certain weight doesn't mean that weight pertains to every type of towable trailer out there. We all know what happens when passing a semi-truck or when they pass us and that effect would be magnified with a longer trailer towed by a lighter vehicle. The force of air has a huge effect. Now this guy's hitch setup and how the trailer was loaded may or may not have played a part in the sway as well......but we will never know. Hopefully the family made it through that without any serious injuries.