Speed has everything to do with high wind roll overs. Ask yourself this. When have you ever seen a parked truck blown over. As for the microburst, that is a phenomenon that occurs in a severe thunderstorm. It has to do with a collapsing column of air crashing into the ground, and then spreading out. You're not going to encounter this on just a windy day.
I saw a flipped truck today off i40, he was headed west. Hope the driver is okay, but I didn't see enough of it to tell if he had flipped due to wind or if he'd slid off the road.
I did see another SNI truck on US 78 today. Somehow he'd managed to turn himself completely around and run off the road. I guess he saved a life because I saw no damage to any part of the truck.
Like I said, Mother Nature shouldn't ever been taken lightly.