Any chance of just excavating? or Partial in-ground?
The climate here swings wildly & can get some 50-60mph wind too but no serious tornado. My plastic sheeting/pvc greenhouse withstood some strong wind, but there's no insulation value to it, so it was more about rain-proofing.
'thinking about going partially underground/in-ground to create a growing environment that is stable as possible using little or no electricty. I get a fairly regular SW wind that can be utilized, possibly even a small windmill generator.
ideally need massive(literally) thermal insulation with maximum adjustibility, automatic would be nice.
the reality is i'm a poor bastard pulling a light-dep tarp at 4am.
<--- would totally live in a cave, fuck the world!