If I had to shoot from the hip,I'd say that in a pure crosswind condition the van is at around Cd 0.85.As soon as it is popped,its in full separation,top and both ends,with an enormous leeward wake.The delta-p just sucks it over.
With less packaging efficiency,an Airstream trailer,with its generous corner radii allows for attached flow over and around, with even a smidegeon of pressure recovery on its leeward side before separation occurs,generating half the wake volume.
And I agree with others with respect to the side skirts having little or no contribution to the roll moment.
The position and magnitude of the C.P. overwhelms the mass and C.G..
Maybe some water bladder low profile ballast until you can get better protection? Pull the cork when you're near ready to roll.I know its a waste of H2o,although it could be captured and recycled.
Hard to stomach the photos! Glad it wasn't any worse.You've got a lot of skin in the game,I hope in the long run that you'll be able to look back and laugh.
I've been humbled by the air many a time.
