Originally Posted by Mule Skinner
If multiple-kilometer-high waves penetrate the continent, all our troubles are over.
I have read Uriel's Machine. While the Authors are able to draw together a wide range of evidence (some I did not know existed) that does not necessarily prove their conclusions are correct. Still it is a very interesting read.
What I took away was, the Earth gets hit with objects big enough to disrupt our magnetic field, roughly once every 2,000 yrs.
An object of that size makes a very large hole, and a direct hit would destroy a major city. The total impact is much like the eruption from a mega volcano, and a Year Without A Summer is one possible result.