If you’re thinking about a greenhouse, the first thing that comes to mind is probably big glass panels, but glass can be fragile, especially when dealing with snow. When buying a greenhouse kit, synthetic materials are now more common. For a bit more durability, consider a material like polycarbonate sheets that are rigid and clear like glass but better able to deal with the weight and abuse of snow and other weather. Just be careful to see if it yellows over time, as yellowing polycarbonate can change the light that reaches plants. Also, consider polyvinyl chloride, or PVC. It is flexible, lightweight, affordable, durable, and able to handle heavy snow loads. If you get UV treatments, PVC will even resist yellowing.