Well, we were near Craters of the Moon returning from an Oregon coast trip and we passed what looked like a Tacoma with an Eagle(?) with the top still popped up traveling down the highway. I didn't have much time to confirm that it was indeed a FWC fully popped up since we passed on a curve, but I waved wildly and flashed my lights and pointed only to get a casual wave back through tinted windows. Normally I probably would've just kept going feeling like I tried and Darwin was smiling down on that camper, but being a fellow FWC owner I stopped and turned my truck around and tried to give chase. After getting a crew cab f350 turned around and going thru the gears as fast as I could and leaving plenty of black smoke, I gave up after about 10 minutes of 75-80 mph pursuit unable to catch them.
So I guess the take away of the story is, a popped up FWC can sustain 70+ mph highway winds, at least for a certain amount of time. The glimpse I got in passing showed the grey sideliner fabric rippling erratically and the roof bobbing up and down a little bit with what must of been the lift panel flexing. Hopefully all ended well, I never did find a camper roof in the road or saw any carnage pictures on this website. Double check your roofs before travel!!