I tried a hoop coop, and over night the snow crushed it. (Thank goodness no chickens were in it!) So I have to have a steep not round coop. I make hoop coops for the summer then just take the tarps off in the winter so they don't get destroyed, I have to have 2 different types of coops, winter coops then I have Spring, Summer coops.
Could you show us a pic? I'm thinking we are talking about two different things here, as a hoop coop is pretty strong under a snow load because of it's arched design and even that can be reinforced with a wooden framework if you get more than 2 panels in your design. Usually two panels are fine on their own, but adding a third panel seems to make a hoop coop a little more vulnerable. As Bruce said, it also depends on the degree of arch you are using as well.
Mine bears a couple of feet or more of wet snow without any problems whatsoever and even more so now that I've added a support beam under the arch the whole length of the three panels. I've had over 2 ft. of snow on this and it didn't even move the arch at all...and it's super easy to get the snow off by flexing the panels from inside and the snow just slides off the sides.