I should remember this, but I don't.
What is a derecho?
Well, actually will have to check if it met the formal definition....
But essentially what went through St. Louis was a curved line of thunderstorms with extreme straight line winds. Even if there were any embedded tornadoes 99% of the damage will turn out to have been caused by straight line winds.
There's a curious inability of the public to accept that you can have serious wind damage from anything that isn't a tornado - Derechos, downbursts, etc.