I agree that I'm not sure this was gale force winds.
It is possible that a number of very big guys could have toppled it. It is a tall narrow slab that is only anchored at the base with probably silicone sealant.
We have incredibly strong wind gusts here too. We saw some last night as a storm moved past us. We caught the southern edge of the storm moving from the SW to the NE. I was a my father’s to help him get ready for bed (he’s 92) and the noises and banging and pinking of light hail were unsettling.