By the way, here is my previous design, which I mostly copied off another market gardener on the gardenweb forum:
Against a wind storm, the low and flat design is very strong. I think it would take an F1 tornado to blow it away.
But against snow load, it is no match, especially a super-storm that drops 8" of accumulated sleet under the snow:
So that's why the new design has such a steep roof. But now I am going to catch wind exponentially more than with the low design.
I repaired the smashed tunnel and re-used all the old pipe I could. The collapse cost me about $40.