I don’t think I can have a greenhouse in that spot either, if it’s covered over the top...
Does the greenhouse you’re looking to get come with a roof? A slanted polycarbonate roof or something? If it does, and the roof isn’t meant to come off after the growing season ends, then I’m guessing it must be built sturdy enough to withstand snow. The sides acting as sails aside, I’d worry more about the roof. If it wasn’t meant as an all-weather roof, I wouldn’t trust it in the winter without some heavy reinforcements. I made that mistake last year. Bought a large greenhouse frame for my garden and wrapped it in chicken wire to keep the birds and rabbits out. I didn’t even put plastic over it, just the chicken wire, thinking the snow would fall through the holes... Ha ha ha. First decent snowfall and the frame was bent to sh**, almost down to the ground!!! I can only imagine if it had plastic over it as well. I’ll need to disassemble it now and build custom supports to hold it up for next winter. Or for this summer, for that matter - I can’t stand up under it right now, it’s so bent and crushed down