I damaged my van due to wind.
But it wasn't the penthouse per se, it was the crossbar spanning the top of the van just behind the driver's seat, where the top latches down. The thing is part wood, and the upthrust of the top in the wind gust pulled it up and broke it.
It occurred as I was driving US 50 in about 50 MPH gusts at about 65 MPH; wind apparently got under the front of the penthouse via those runnels in the Ford cab roof. It pumped up the canvas like an airbag, which jacked the whole penthouse up several inches (the back latch held). I used tie down ratchets to hold it to the floor, and got it repaired at SMB West (FREE, thank you thank you).
Important to note it did NO damage whatsoever to the penthouse or the canvas.
Another time I popped the penthouse in 75 MPH winds (self generated as I bombe down the Coquihalla Hwy). Turns out if you don't latch it, it will open on its own at that speed. Pulled over, latched it. No damage whatsoever.
So don't even post about your piddly little desert zephyr...nothing to see there, and no worries
And you can all thank me for my rigorous product testing (and I'm sure I won't get many carpoolers...).
Seriously, though, I also put it down in 35+ winds due to the motion; keeps me awake.