We experienced similar failures for our Shelter Logic exterior structures - I think cover it is one of their brands. Both of these structures have made it through several years of hurricanes, winter storms and more, but not this time.
This was my outside workshop and storage ... as you can see Sandy picked up one corner of this one off the ground and moved it over. Unfortunately that was the corner that we couldn't twist the anchor down *all* the way. The winds were strong enough to push that huge compressor aside and turn it on its head.
In it's defense, the structure held up pretty well. This unit is bolted together at each connection point and it's seen a few years so there were some tears in the zip up door on one side that I'm sure tore further and helped the wind to get in.
This is a similar structure/greenhouse in our yard, just a little smaller and this one does not bolt together. I used ratchet straps to keep the structure tight, but Sandy was a little too much for it.
Guess we're looking at a couple of covers and likely a few bent poles here and there.
60Vette - the Shelter Logic manufacturing facility is right in Watertown, CT - only about 25 mins from where we are. You can buy replacement parts from them directly ShelterLogic
It's close enough to us that I buy all shelters (and parts when needed) right from them and save the shipping costs as these units are heavy and are relatively expensive to ship