At what wind speed mph would you consider?

I almost never guy-line out my tent. If the anchor stakes and all of my gear cannot hold my tent, then I should not be there, either. In 40 MPH winds in the tundra, my tent has not rolled until I removed my gear and anchors, then I chased it across a couple of football fields' worth of tundra meadow at 12,500 feet. Running can be difficult across a tundra meadow and boulder field at 12,500 feet.