“I wonder how strong those winds were.”
Not strong enough to blow those people away.
The question is how fresh was the concrete?
Very, It looks like.
Don’t they need a week or so to be full strength?
I Found this:
https://www.powerblanket.com/blog/long-concrete-take-set/
Curing Time for Concrete. In standard industrial cases,
full strength concrete is recognized at 28 days. At seven
days, you should have concrete that is cured to 70% full
strength or greater. But to answer the question of, “How
long does concrete take to set?” concrete setting time is
generally 24 to 48 hours.
~Easy
Only thing we know for certain about this right now is Murphy’s Law is still valid.
Under construction looked like for sure.