Comets Over Canada

I have written here about the theory that the Younger Dryas, an 1,500 year long period of extreme cold that took place between about 13,000 and 11,500 years ago, was triggered by an "impact event" occurring somewhere over Canada. Well, more evidence in favor of this new theory has recently turned up:

Samples of diamonds, gold and silver that have been found in the region have been conclusively sourced through X-ray diffractometry in the lab of UC Professor of Geology Warren Huff back to the diamond fields region of Canada.

The only plausible scenario available now for explaining their presence this far south is the kind of cataclysmic explosive event described by West’s theory. "We believe this is the strongest evidence yet indicating a comet impact in that time period," says Tankersley.

Fascinating stuff. But I cannot get this to jibe with earlier articulations of the theory. Specifically, geophysicist Allen West has previously suggested that the impactor exploded before touching ground (a la the Tunguska Event), this to explain the absence of a crater. But how could diamonds originating in the Canadian diamond fields have turned up so far South if not as ejecta from a (still undiscovered) crater?