I did not read every post in this thread so if what I am saying has all ready been mentioned....
That tree wasnt hit by lightening. Most of the time a tree takes a hit by lightening there is some discoloration just beneath the bark, with bits of bark missing. You will see this most where it enterd & exited, with bits of bark scatterd about below on the ground.
With this tree being hollow it makes it susceptable to this type of fracture.
If any of you camp & stick it out in a storm,watch the trees. It is nothing short of amazing just how much a tree will twist & rotate during a storm.