Two winters ago during our Christmas break from work (I had 16 days off) and we had a big winter storm come through that dumped a lot of snow on us that stuck around for about a week.
I prepared for it by stocking up on extra groceries, and my rig did not move for around a good 10 days or so.
The Maggiolina shell had around 1' of frozen snow on it (not sure how much that weighs) the whole time, and after the thaw the shell was not damaged in anyway.
Suppose to get a nasty winter this year according to the weather experts, so if we get a lot this year, I will sweep some of the snow off to be on the safe side.
What I like about the Maggiolina tents too is after our very wet winters and springs here, when I go to open up the tent to take the sheets out to wash them, there is no dust/dirt inside or wetness at all.
They seal as good as they state on their website.