We don't even know the frequency of this
I think the last large object to actually hit that we know of was after WWII in Eastern Siberia, on the same latitude as Moscow. If I remember, it was around 1947 and was the equivalent of a Hiorshima sized bomb.
We do kiloton sized explosions in the upper atmosphere fairly often.
But are we getting a cluster of debris right now, or is this a normal NEO frequency?
WE just don't know, and the lesson could be really expensive.
Ed