I was thinking wind would be the bigger issue, so I always keep it closed up and the sides tied down.
Was yours open?
Someone suggested that I run a few lines under the car, tied to both sides of the canopy, to keep it down in the off season winds.
It was closed, but a sudden spring storm, 80mph winds, this thing was sitting on the open side of the field, it ended up being a huge parachute, lol.
My weeping willow stopped it (the shelter) from rolling over my neighbours shed and deck.