marduk
quelling chaos since 2352BC
I don't have Stanford's book. I should get a copy sometime. However it's not necessary in order to address this issue. I have reviewed the CUFOs case files which you might be interested in because they include copies of original correspondence between Stanford and Richard Hall at NICAP, plus Zamora's report and a variety of other clips. Maybe I overlooked it, but in none of that documentation did I see anything that mentions flames "knifing into the ground", and as already stated, there's no way to be certain that is an accurate observation given the variables involved anyway.
Just bounced a quick note off of Ray, and he's confirming the description is accurate, and he went into it in some detail with Zamora. The flame appeared to go into the ground, leaving no hole when it left.
That's what Zamora said he saw, at any rate.