Indeed a swarm event is exactly what we're talking about. My thinking at this point is that the Earth must have passed through the debris field of the Taurid Progenitor object soon after it's complete breakup. See W. M. Napier's 'Palaeolithic extinctions and the Taurid Complex'.
https://dl.dropboxusercontent.com/u/2268163/Paleolithic%20extinctions.pdf
The Earth moves along her own orbital path at something like 8.4 times her own width in an hour. So the main event would've been concentrated on one side of the planet, and over with in about an hour. But we are also expecting to find evidence of annual return engagements with the debris from the Taurids for millennia afterwards each time the Earth's orbit coincided with that of the highest concentrations of remaining fragments in the Taurid Complex.
And the scariest realization of all is that the Taurids aren't through with us yet. Sooner or later the orbital resonances of the Earth, and the Taurid Complex will line up again to make it rain fire again.
