I think that the roof is pretty resilient, vents uncovered may break. Aluminum sided units would be more likely to dent than the smooth sided. Mine have been in a few hail storms (NY State style is not bad at all) and came through without a scratch.
Karl - Southeast, NY
2020 377 RLBH
2018 Ram 3500 Mega Limited 6.7L Cummins w/ Aisin
My bathroom vent cover was shredded in a hail storm and the screen frame was broken as well and they were quarter size, but they were coming done like a heavy rain. The new one I have is supposed to be nearly unbreakable, well so they claim.
Well, we didn't take any chances when a storm come rolling in. We live less than five miles from the campground, so when we saw the radar looking VERY dicey, we tucked our tail and ran and put the TT in the barn! One good thing though, I got alot of practice on setting up and breaking down the new TT!
Caught a freak hail storm in the middle of Wyoming last year. Trailer is rubber roof and aluminum sided. Dents on the front that happeened before I could get stopped - bathroom vent cover broken.
Insurance paid to replace all - but honestly with the small dents on the front panels I elected to not repair it. Something else happens and it will likely decrease my claim - but worth the risk IMHO. It was about $3000 to do the work!
Put a Maxx-Air cover over the broken vent and life is good....